Base station apparatus, terminal apparatus, and wireless communication method

ABSTRACT

A base station apparatus includes a transmission unit that transmits first information indicating a first configuration, second information indicating a second configuration, and third information indicating a third configuration, in which the first configuration is used to determine a correspondence between a subframe in which a PDCCH is allocated and a subframe in which a PUSCH corresponding to the PDCCH is allocated, in which the second configuration is an element of a configuration set which is restricted on the basis of the first configuration, and is used to determine a correspondence between a subframe in which a PDSCH is allocated and a subframe in which a HARQ-ACK corresponding to the PDSCH is transmitted, and in which the third configuration is an element of a configuration set which is restricted on the basis of the first configuration and the second configuration, and is used to specify a subframe in which the PDCCH is monitored.

TECHNICAL FIELD

The present invention relates to a base station apparatus, a terminalapparatus, and a wireless communication method.

BACKGROUND ART

A radio access method and a radio network (hereinafter, referred to asLong-Term Evolution (LTE) or Evolved Universal Terrestrial Radio Access(EUTRA)) of cellular mobile communication have been examined in theThird Generation Partnership Project (3GPP). In LTE, an orthogonalfrequency division multiplexing (OFDM) method is used as a downlinkcommunication method. In LTE, a single-carrier frequency divisionmultiple access (SC-FDMA) method is used as an uplink communicationmethod. In LTE, a base station apparatus is also referred to as evolvedNodeB (eNodeB), and a mobile station apparatus is also referred to asuser equipment (UE). LTE is a cellular communication system in which aplurality of areas covered by a base station apparatus are allocated ina cell form. A single base station apparatus may manage a plurality ofcells.

LTE corresponds to time division duplex (TDD). LTE employing the TDD isalso referred to as TD-LTE or LTE TDD. The TDD is a technique which canrealize full-duplex communication in a single frequency band throughtime division multiplexing of an uplink signal and a downlink signal.

In 3GPP, it has been examined that a traffic adaptation technique and aninterference reduction technique (DL-UL interference management andtraffic adaptation) in which a ratio of an uplink resource and adownlink resource is changed depending on uplink traffic and downlinktraffic are applied to the TD-LTE.

In NPL 1, a method of using a flexible subframe is proposed as a methodof realizing traffic adaptation. A base station apparatus can receive anuplink signal or transmit a downlink signal in a flexible subframe. InNPL 1, a mobile station apparatus regards the flexible subframe as adownlink subframe unless the mobile station apparatus is instructed totransmit an uplink signal in the flexible subframe by the base stationapparatus. The traffic adaptation technique is also referred to asdynamic TDD.

NPL 1 discloses that a hybrid automatic repeat request (HARQ) timing fora physical downlink shared channel (PDSCH) is determined on the basis ofan uplink-downlink configuration which is newly introduced, and thatHARQ timing of a physical uplink shared channel (PUSCH) is determined onthe basis of the initial UL-DL configuration.

NPL 2 discloses that (a) a UL/DL reference configuration is introduced,and (b) several subframes may be scheduled to be used for either anuplink or a downlink through dynamic grant/assignment from a scheduler.

CITATION LIST Non Patent Literature

-   NPL 1: “On standardization impact of TDD UL-DL adaptation”,    R1-122016, Ericsson, ST-Ericsson, 3GPP TSG-RAN WG1 Meeting #69,    Prague, Czech Republic, 21 to 25 May 2012.-   NPL 2: “Signaling support for dynamic TDD”, R1-130558, Ericsson,    ST-Ericsson, 3GPP TSG-RAN WG1 Meeting #72, St Julian's, Malta, 28    Jan. to 1 Feb. 2013.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Throughput can be considerably improved in a case where the trafficadaptation technique is applied compared with a case where the ratio ofan uplink resource and a downlink resource is not changed. However, in acase where a terminal apparatus erroneously receives/decodes schedulinginformation from a scheduler, there is a problem in that the terminalapparatus transmits an uplink signal in a subframe in which a basestation apparatus transmits a downlink signal to another terminalapparatus, and thus the uplink signal interferes with the downlinksignal.

The present invention has been made in consideration of the abovecircumstances, and an object thereof is to provide a base stationapparatus, a terminal apparatus, an integrated circuit, and a radiocommunication method, capable of reducing the probability that theterminal apparatus may erroneously transmit an uplink signal.

Means for Solving the Problems

(1) In order to achieve the above-described object, the presentinvention provides the following means. In other words, according to thepresent invention, there is provided a base station apparatus whichperforms communication with a terminal apparatus, the base stationapparatus including a transmission unit that transmits first informationindicating a first configuration, second information indicating a secondconfiguration, and third information indicating a third configuration,in which the first configuration is used to determine a correspondencebetween a subframe in which a physical downlink control channel isallocated and a subframe in which a physical uplink shared channelcorresponding to the physical downlink control channel is allocated, inwhich the second configuration is an element of a configuration setwhich is restricted on the basis of the first configuration, and is usedto determine a correspondence between a subframe in which a physicaldownlink shared channel is allocated and a subframe in which a HARQ-ACKcorresponding to the physical downlink shared channel is transmitted,and in which the third configuration is an element of a configurationset which is restricted on the basis of the first configuration and thesecond configuration, and is used to indicate a subframe in which thephysical downlink control channel is monitored.

(2) In addition, according to the present invention, there is provided aterminal apparatus which performs communication with a base stationapparatus, the terminal apparatus including a reception unit thatreceives first information indicating a first configuration, secondinformation indicating a second configuration, and third informationindicating a third configuration; and a setting unit that sets the firstconfiguration, the second configuration, and the third configuration, inwhich the first configuration is used to determine a correspondencebetween a subframe in which a physical downlink control channel isallocated and a subframe in which a physical uplink shared channelcorresponding to the physical downlink control channel is allocated, inwhich the second configuration is an element of a configuration setwhich is restricted on the basis of the first configuration, and is usedto determine a correspondence between a subframe in which a physicaldownlink shared channel is allocated and a subframe in which a HARQ-ACKcorresponding to the physical downlink shared channel is transmitted,and in which the third configuration is an element of a configurationset which is restricted on the basis of the first configuration and thesecond configuration, and is used to specify a subframe in which thephysical downlink control channel is monitored.

(3) In addition, according to the present invention, there is providedan integrated circuit mounted in a base station apparatus which performscommunication with a terminal apparatus, the integrated circuit causingthe base station apparatus to realize a series of functions including afunction of transmitting first information indicating a firstconfiguration; a function of transmitting second information indicatinga second configuration; and a function of transmitting third informationindicating a third configuration, in which the first configuration isused to determine a correspondence between a subframe in which aphysical downlink control channel is allocated and a subframe in which aphysical uplink shared channel corresponding to the physical downlinkcontrol channel is allocated, in which the second configuration is anelement of a configuration set which is restricted on the basis of thefirst configuration, and is used to determine a correspondence between asubframe in which a physical downlink shared channel is allocated and asubframe in which a HARQ-ACK corresponding to the physical downlinkshared channel is transmitted, and in which the third configuration isan element of a configuration set which is restricted on the basis ofthe first configuration and the second configuration, and is used tospecify a subframe in which the physical downlink control channel ismonitored.

(4) In addition, according to the present invention, there is providedan integrated circuit mounted in a terminal apparatus which performscommunication with a base station apparatus, the integrated circuitcausing the terminal apparatus to realize a function of receiving firstinformation indicating a first configuration, second informationindicating a second configuration, and third information indicating athird configuration; and a function of setting the first configuration,the second configuration, and the third configuration, in which thefirst configuration is used to determine a correspondence between asubframe in which a physical downlink control channel is allocated and asubframe in which a physical uplink shared channel corresponding to thephysical downlink control channel is allocated, in which the secondconfiguration is an element of a configuration set which is restrictedon the basis of the first configuration, and is used to determine acorrespondence between a subframe in which a physical downlink sharedchannel is allocated and a subframe in which a HARQ-ACK corresponding tothe physical downlink shared channel is transmitted, and in which thethird configuration is an element of a configuration set which isrestricted on the basis of the first configuration and the secondconfiguration, and is used to specify a subframe in which the physicaldownlink control channel is monitored.

(5) In addition, according to the present invention, there is provided aradio communication method used for a base station apparatus whichperforms communication with a terminal apparatus, the method includingtransmitting first information indicating a first configuration, secondinformation indicating a second configuration, and third informationindicating a third configuration, in which the first configuration isused to determine a correspondence between a subframe in which aphysical downlink control channel is allocated and a subframe in which aphysical uplink shared channel corresponding to the physical downlinkcontrol channel is allocated, in which the second configuration is anelement of a configuration set which is restricted on the basis of thefirst configuration, and is used to determine a correspondence between asubframe in which a physical downlink shared channel is allocated and asubframe in which a HARQ-ACK corresponding to the physical downlinkshared channel is transmitted, and in which the third configuration isan element of a configuration set which is restricted on the basis ofthe first configuration and the second configuration, and is used toindicate a subframe in which the physical downlink control channel ismonitored.

(6) In addition, according to the present invention, there is provided aradio communication method used for a terminal apparatus which performscommunication with a base station apparatus, the method includingreceiving first information indicating a first configuration, secondinformation indicating a second configuration, and third informationindicating a third configuration; and setting the first configuration,the second configuration, and the third configuration, in which thefirst configuration is used to determine a correspondence between asubframe in which a physical downlink control channel is allocated and asubframe in which a physical uplink shared channel corresponding to thephysical downlink control channel is allocated, in which the secondconfiguration is an element of a configuration set which is restrictedon the basis of the first configuration, and is used to determine acorrespondence between a subframe in which a physical downlink sharedchannel is allocated and a subframe in which a HARQ-ACK corresponding tothe physical downlink shared channel is transmitted, and in which thethird configuration is an element of a configuration set which isrestricted on the basis of the first configuration and the secondconfiguration, and is used to specify a subframe in which the physicaldownlink control channel is monitored.

Effects of the Invention

According to the present invention, it is possible to reduce aprobability that a terminal apparatus may erroneously transmit an uplinksignal.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a conceptual diagram of a radio communication system of thepresent embodiment.

FIG. 2 is a diagram illustrating a schematic configuration of a radioframe of the present embodiment.

FIG. 3 is a diagram illustrating a configuration of a slot of thepresent embodiment.

FIG. 4 is a diagram illustrating an example in which a physical channeland a physical signal are mapped in a downlink subframe of the presentembodiment.

FIG. 5 is a diagram illustrating an example in which a physical channeland a physical signal are mapped in an uplink subframe of the presentembodiment.

FIG. 6 is a diagram illustrating an example in which a physical channeland a physical signal are mapped in a special subframe of the presentembodiment.

FIG. 7 is a schematic block diagram illustrating a configuration of amobile station apparatus 1 of the present embodiment.

FIG. 8 is a schematic block diagram illustrating a configuration of abase station apparatus 3 of the present embodiment.

FIG. 9 is a table illustrating an example of an uplink-downlinkconfiguration in the present embodiment.

FIG. 10 is a diagram illustrating a correspondence between a subframe nin which PDCCH/EPDCCH/PHICH is allocated, and a subframe n+k in which aPUSCH corresponding to the PDCCH/EPDCCH/PHICH is allocated, in thepresent embodiment.

FIG. 11 is a diagram illustrating a correspondence between a subframe nin which a PHICH is allocated, and a subframe n−k in which a PUSCHcorresponding to the PHICH is allocated, in the present embodiment.

FIG. 12 is a diagram illustrating a correspondence between a subframe nin which a PUSCH is allocated, and a subframe n+k in which a PHICHcorresponding to the PUSCH is allocated, in the present embodiment.

FIG. 13 is a diagram illustrating a correspondence between a subframen−k in which a PDSCH is allocated, and a subframe n in which a HARQ-ACKcorresponding to the PDSCH is transmitted, in the present embodiment.

FIG. 14 is a diagram illustrating a relationship between a subframeindicated by an uplink reference configuration and a subframe indicatedby a downlink reference configuration in a first embodiment of thepresent invention.

FIG. 15 is a diagram illustrating a relationship between a subframeindicated by an uplink reference configuration, a subframe indicated bya downlink reference configuration, and a subframe indicated by atransmission direction configuration, in the first embodiment of thepresent invention.

FIG. 16 is a diagram illustrating a relationship between an uplinkreference configuration, a downlink reference configuration, and atransmission direction configuration, in the first embodiment of thepresent invention.

FIG. 17 is a diagram illustrating an example of communication betweenthe base station apparatus 3 and the mobile station apparatuses 1 (1Aand 1B) in the first embodiment of the present invention.

FIG. 18 is a diagram illustrating a relationship between an uplinkreference configuration, a downlink reference configuration, and atransmission direction configuration, in a second embodiment of thepresent invention.

FIG. 19 is a sequence diagram illustrating an example of a thirdembodiment of the present invention.

FIG. 20 is a sequence diagram illustrating an example of a fourthembodiment of the present invention.

FIG. 21 is a diagram illustrating an example of a fifth embodiment ofthe present invention.

MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described.

In the present embodiment, a single cell is set for a mobile stationapparatus. The present invention may be applied to each of a pluralityof cells set for the mobile station apparatus. A technique in which themobile station apparatus performs communication with the plurality ofcells is referred to as cell aggregation or carrier aggregation. Inaddition, the present invention may be applied to some of the pluralityof set cells. The cell set for the mobile station apparatus is alsoreferred to as a serving cell.

A radio communication system of the present embodiment employs a timedivision duplex (TDD) method. In a case of cell aggregation, the TDDmethod may be applied to each of a plurality of cells.

In a case where a plurality of cells to which the TDD is applied areaggregated, a half-duplex TDD method or a full-duplex TDD method isapplied thereto. In the half-duplex TDD method, a mobile stationapparatus cannot simultaneously perform uplink transmission and downlinkreception in the plurality of cells to which the TDD is applied. In thefull-duplex TDD method, the mobile station apparatus can simultaneouslyperform uplink transmission and downlink reception in a plurality ofcells to which the TDD is applied.

In a case where a cell to which the TDD is applied and a cell to whichfrequency division duplex (FDD) is applied are aggregated, the presentinvention is applicable to the cell to which the TDD is applied.

In the present embodiment, “X/Y” indicates “X or Y”. In the presentembodiment, “X/Y” indicates “X and Y”. In the present embodiment, “X/Y”indicates “X and/or Y”.

FIG. 1 is a conceptual diagram of a radio communication system of thepresent embodiment. In FIG. 1, the radio communication system includesmobile station apparatuses 1A to 1C, and a base station apparatus 3.Hereinafter, the mobile station apparatuses 1A to 1C are referred to aas “mobile station apparatus 1”.

A physical channel and a physical signal of the present embodiment willbe described.

In FIG. 1, the following uplink physical channels are used for uplinkradio communication from the mobile station apparatus 1 to the basestation apparatus 3. The uplink physical channels are used to transmitinformation which is output from a higher layer.

-   -   Physical uplink control channel (PUCCH)    -   Physical uplink shared channel (PUSCH)    -   Physical random access channel (PRACH)

The PUCCH is a physical channel used to transmit uplink controlinformation (UCI). The uplink control information includes channel stateinformation (CSI) of downlink, a scheduling request (SR) indicating arequest for a PUSCH resource, and acknowledgement (ACK)/negative ACK(NACK) for downlink data (transport block, downlink-shared channel:DL-SCH). The ACK/NACK is also referred to as a HARQ-ACK, HARQ feedback,or response information.

The PUSCH is a physical channel used to transmit uplink data(uplink-shared channel: UL-SCH). In addition, the PUSCH may be used totransmit the ACK/NACK and/or the channel state information along withthe uplink data. Further, the PUSCH may be used to transmit only thechannel state information, or only the ACK/NACK and the channel stateinformation.

The PRACH is a physical channel used to transmit a random accesspreamble. The PRACH is mainly used for the mobile station apparatus 1 tobe synchronized with the base station apparatus 3 in a time domain. Inaddition, the PRACH is also used to indicate synchronization (timingadjustment) with an initial connection establishment procedure, ahandover procedure, a connection reestablishment procedure, and uplinktransmission, and to indicate a request for a PUSCH resource.

In FIG. 1, the following uplink physical signal is used for the uplinkradio communication. The uplink physical signal is not used to transmitinformation output from a high layer but is used by a physical layer.

-   -   Uplink reference signal (UL RS)

In the present embodiment, the following two types of uplink referencesignals are used.

-   -   Demodulation reference signal (DMRS)    -   Sounding reference signal (SRS)

The DMRS is related to transmission of the PUSCH or the PUCCH. The DMRSis subject to time division multiplexing with the PUSCH or the PUCCH.The base station apparatus 3 uses the DMRS to perform channel correctionof the PUSCH or the PUCCH. Hereinafter, transmission of both the PUSCHand the DMRS is simply referred to transmission of the PUSCH.Hereinafter, transmission of both the PUCCH and the DMRS is simplyreferred to transmission of the PUCCH.

The SRS is not related to transmission of the PUSCH or the PUCCH. Thebase station apparatus 3 uses the SRS to measure an uplink channelstate. The mobile station apparatus 1 transmits a first SRS in a firstresource which is set by a high layer. In addition, in a case whereinformation indicating a request for transmitting the SRS is receivedvia a PDCCH, the mobile station apparatus 1 transmits a second SRS onlyonce in a second resource which is set by the high layer. The first SRSis also referred to as a periodic SRS. The second SRS is also referredto as an aperiodic SRS.

In FIG. 1, the following downlink physical channels are used fordownlink radio communication from the base station apparatus 3 to themobile station apparatus 1. The downlink physical channels are used totransmit information output from a high layer.

-   -   Physical broadcast channel (PBCH)    -   Physical control format indicator channel (PCFICH)    -   Physical hybrid automatic repeat request indicator channel        (PHICH)    -   Physical downlink control channel (PDCCH)    -   Enhanced physical downlink control channel (EPDCCH)    -   Physical downlink shared channel (PDSCH)

The PBCH is used to send a notification of master information block(MIB, or broadcast channel: BCH) which is used in common by the mobilestation apparatuses 1. The MIB is transmitted at intervals of 40 ms, andthe MIB is repeatedly transmitted with periodicity of 10 ms.Specifically, initial transmission of the MIB is performed in a subframe0 of a radio frame satisfying SFN mod 4=0, and retransmission(repetition) of the MIB is performed in subframes 0 of all other radioframes. The SFN (system frame number) is a radio frame number. The MIBis system information. For example, the MIB includes informationindicating the SFN.

The PCFICH is used to transmit information indicating a region (OFDMsymbol) which is used to transmit the PDCCH.

The PHICH is used to transmit a HARQ indicator (HARQ feedback orresponse information) indicating an acknowledgement (ACK) or negativeacknowledgement (NACK) of uplink data (uplink shared channel: UL-SCH)received by the base station apparatus 3. For example, in a case where aHARQ indicator indicating an ACK is received, the mobile stationapparatus 1 does not retransmit corresponding uplink data. For example,in a case where a HARQ indicator indicating a NACK is received, themobile station apparatus 1 retransmits corresponding uplink data. Asingle PHICH transmits a HARQ indicator for a single item of uplinkdata. The base station apparatus 3 transmits respective HARQ indicatorsfor a plurality of uplink data items included in the same PUSCH, byusing a plurality of PHICHs.

The PDCCH and the EPDCCH are used to transmit downlink controlinformation (DCI). The downlink control information is also referred toas a DCI format. The downlink control information includes a downlinkgrant (also referred to as downlink assignment) and an uplink grant. Thedownlink grant is downlink control information used for scheduling asingle PDSCH in a single cell. The downlink grant is used for schedulinga PDSCH in the same subframe as a subframe in which the downlink grantis transmitted. The uplink grant is downlink control information usedfor scheduling a single PUSCH in a single cell. The uplink grant is usedfor scheduling a single PUSCH in a subframe which occurs four or moresubframes later than a subframe in which the uplink grant istransmitted.

A cyclic redundancy check (CRC) parity bit is added to the DCI format.The CRC parity bit is scrambled with a cell-radio network temporaryidentifier (C-RNTI), or a semi-persistent scheduling cell-radio networktemporary identifier (SPS C-RNTI). The C-RNTI and the SPS C-RNTI areidentifiers for identifying a mobile station apparatus in a cell.

The C-RNTI is used to control the PDSCH or the PUSCH in a singlesubframe. The SPS C-RNTI is used to periodically allocate a PDSCH orPUSCH resource.

The PDSCH is used to transmit downlink data (downlink shared channel:DL-SCH).

In FIG. 1, the following downlink physical signals are used for thedownlink radio communication. The downlink physical signals are not usedto transmit information output from a high layer but are used by aphysical layer.

-   -   Synchronization signal (SS)    -   Downlink reference signal (DL RS)

The synchronization signal is used for the mobile station apparatus 1 toperform synchronization of a frequency domain and a time domain of adownlink. The downlink reference signal is used for the mobile stationapparatus 1 to perform channel correction of the downlink physicalchannel. The downlink reference signal is used for the mobile stationapparatus 1 to calculate channel state information of a downlink. In theTDD method, the synchronization signal is mapped in subframes 0, 1, 5and 6 of a radio frame. In the FDD method, the synchronization signal ismapped only in subframes 0 and 5 of a radio frame.

In the present embodiment, the following five types of downlinkreference signals are used.

-   -   Cell-specific reference signal (CRS)    -   UE-specific reference signal (URS) related to a PDSCH    -   Demodulation reference signal (DMRS) related to an EPDCCH    -   Non-zero power channel state information—reference signal (NZP        CSI-RS)    -   Zero power channel state information—reference signal (ZP        CSI-RS)

The CRS is transmitted with every one of the subframes. The CRS is usedto demodulate PBCH/PDCCH/PHICH/PCFICH/PDSCH. The CRS may be used for themobile station apparatus 1 to calculate channel state information of adownlink. The PBCH/PDCCH/PHICH/PCFICH are (is) transmitted via anantenna port which is used to transmit the CRS.

The URS related to a PDSCH is transmitted with a subframe and a bandwhich are used to transmit the PDSCH to which the URS is related. TheURS is used to demodulate a PDSCH to which the URS is related.

The PDSCH is transmitted via an antenna port which is used to transmit aCRS or a URS. A DCI format 1A is used for scheduling a PDSCH which istransmitted via an antenna port used to transmit a CRS. A DCI format 2Dis used for scheduling a PDSCH which is transmitted via an antenna portused to transmit a URS.

The DMRS related to an EPDCCH is transmitted with a subframe and a bandwhich are used to transmit the EPDCCH to which the DMRS is related. TheDMRS is used to demodulate an EPDCCH to which the DMRS is related. TheEPDCCH is transmitted via an antenna port which is used to transmit theDMRS.

The NZP CSI-RS is transmitted in a set subframe. A resource in which theNZP CSI-RS is transmitted is set by the base station apparatus. The NZPCSI-RS is used for the mobile station apparatus 1 to calculate channelstate information of downlink.

A resource of the ZP CSI-RS is set by the base station apparatus. Thebase station apparatus does not transmit the ZP CSI-RS. The base stationapparatus does not transmit a PDSCH and an EPDCCH in a set resource ofthe ZP CSI-RS. For example, the mobile station apparatus can measurechannel state information by using a CSI-RS in a certain cell which doesnot interfere with an adjacent cell, by setting a resource transmittedvia the NZP CSI-RS in the certain cell as a resource transmitted via theZP CSI-RS in the adjacent cell.

The downlink physical channel and the downlink physical signal arecollectively referred to as a downlink signal. The uplink physicalchannel and the uplink physical signal are collectively referred to asan uplink signal. The downlink physical channel and the uplink physicalchannel are collectively referred to as a physical channel. The downlinkphysical signal and the uplink physical signal are collectively referredto a physical signal.

The BCH, UL-SCH and DL-SCH are transport channels. A channel used by amedium access control (MAC) layer is referred to as a transport channel.The unit of the transport channel used by the MAC layer is referred toas a transport block (TB) or a MAC protocol data unit (PDU). In the MAClayer, control of a hybrid automatic repeat request (HARQ) is performedon each transport block. The transport block is the unit of data whichis delivered to a physical layer by the MAC layer. In the physicallayer, the transport block is mapped to a codeword, and a coding processis performed on each codeword.

Hereinafter, a configuration of the radio frame of the presentembodiment will be described.

FIG. 2 is a diagram illustrating a schematic configuration of the radioframe of the present embodiment. Each radio frame has a length of 10 ms.In addition, each radio frame is constituted by two half frames. Each ofthe half frames has a length of 5 ms. Each of the half frames isconstituted by five subframes. Each of the subframes has a length of 1ms and is defined by two consecutive slots. Each of the slots has alength of 0.5 ms. An i-th subframe of the radio frame is constituted bya (2×i)-th slot and a (2×i+1)-th slot. In other words, ten subframes canbe used at intervals of 10 ms.

In the present embodiment, the following three types of subframes aredefined.

-   -   Downlink subframe (first subframe)    -   Uplink subframe (second subframe)    -   Special subframe (third subframe)

The downlink subframe is a subframe which is reserved for downlinktransmission. The uplink subframe is a subframe which is reserved foruplink transmission. The special subframe is constituted by threefields. The three fields are a downlink pilot time slot (DwPTS), a guardperiod (GP), and an uplink pilot time slot (UpPTS). A total length ofthe DwPTS, the GP, and the UpPTS is 1 ms. The DwPTS is a field which isreserved for downlink transmission. The UpPTS is a field which isreserved for uplink transmission. The GP is a field in which downlinktransmission and uplink transmission are not performed. In addition, thespecial subframe may consist of only the DwPTS and GP, and may consistof only the GP and the UpPTS.

A single radio frame is constituted by at least a downlink subframe, anuplink subframe, and a special subframe.

The radio communication system of the present embodiment supports thedownlink-to-uplink switch-point periodicities of 5 ms and 10 ms. In acase where the downlink-to-uplink switch-point periodicity is 5 ms, aspecial subframe is included in both half frames of the radio frame. Ina case where the downlink-to-uplink switch-point periodicity is 10 ms, aspecial subframe is included only in the first half frame of the radioframe.

Hereinafter, a configuration of the slot of the present embodiment willbe described.

FIG. 3 is a diagram illustrating a configuration of the slot of thepresent embodiment. A physical signal or a physical channel transmittedin each slot is expressed by a resource grid. In a downlink, theresource grid is defined by a plurality of subcarriers and a pluralityof OFDM symbols. In an uplink, the resource grid is defined by aplurality of subcarriers and a plurality of SC-FDMA symbols. The numberof subcarriers forming a single slot depends on a bandwidth of a cell.The number of OFDM symbols or SC-FDMA symbols forming a single slot isseven. Each of elements of the resource grid is referred to as aresource element. The resource element is identified by using asubcarrier number and an OFDM symbol number or an SC-FDMA symbol number.

A resource block is used to express mapping of a certain physicalchannel (a PDSCH, a PUSCH, or the like) to a resource element. Theresource block includes a virtual resource block and a physical resourceblock. A certain physical channel is first mapped to the virtualresource block. Then, the virtual resource block is mapped to thephysical resource block. A single physical resource block is defined byseven continuous OFDM symbols or SC-FDMA symbols in the time domain, andtwelve contiguous subcarriers in the frequency domain. Therefore, asingle physical resource block is constituted by (7×12) resourceelements. In addition, a single physical resource block corresponds to asingle slot in the time domain and corresponds to 180 kHz in thefrequency domain. The physical resource block may be numbered from 0 inthe frequency domain.

Hereinafter, a description will be made of a physical channel and aphysical signal transmitted in each subframe.

FIG. 4 is a diagram illustrating an example of an arrangement ofphysical channels and physical signals in a downlink subframe of thepresent embodiment. The base station apparatus 3 may transmit thedownlink physical channels (the PBCH, the PCFICH, the PHICH, the PDCCH,the EPDCCH, and the PDSCH) and the downlink physical signals (thesynchronization signal and the downlink reference signal) in thedownlink subframe. In addition, the PBCH is transmitted only in thesubframe 0 of the radio frame. Further, the downlink reference signal ismapped in resource elements which are distributed in the frequencydomain and the time domain. For simplification of description, thedownlink reference signal is not illustrated in FIG. 4.

In a PDCCH region, a plurality of PDCCHs may be subject to frequency andtime multiplexing. In an EPDCCH region, a plurality of EPDCCHs may besubject to frequency and time multiplexing. In a PDSCH region, aplurality of PDSCHs may be subject to frequency and time multiplexing.The PDCCH and the PDSCH or the EPDCCH may be subject to timemultiplexing. The PDSCH and the EPDCCH may be subject to frequencymultiplexing.

FIG. 5 is a diagram illustrating an example of an arrangement ofphysical channels and physical signals in an uplink subframe of thepresent embodiment. The mobile station apparatus 1 may transmit theuplink physical channels (the PUCCH, the PUSCH, and the PRACH) and theuplink physical signals (the DMRS and the SRS). In a PUCCH region, aplurality of PUCCHs may be subject to frequency, time and codemultiplexing in the uplink subframe. In a PUSCH region, a plurality ofPUSCHs may be subject to frequency and spatial multiplexing. The PUCCHand the PUSCH may be subject to frequency multiplexing. The PRACH may beallocated in a single subframe or across two subframes. In addition, aplurality of PRACHs may be subject to code multiplexing.

The SRS is transmitted by using the last SC-FDMA symbol of the uplinksubframe. In other words, the SRS is mapped in the last SC-FDMA symbolof the uplink subframe. The mobile station apparatus 1 cannotsimultaneously transmit the SRS and the PUCCH/PUSCH/PRACH in a singleSC-FDMA symbol of a single cell.

In a single uplink subframe of a single cell, the mobile stationapparatus 1 can transmit the PUSCH and/or the PUCCH by using SC-FDMAsymbols excluding the last SC-FDMA symbol of the uplink subframe, andcan transmit the SRS by using the last SC-FDMA symbol of the uplinksubframe. In other words, in the single uplink subframe of the singlecell, the mobile station apparatus 1 can transmit both the SRS and thePUSCH/PUCCH. In addition, the DMRS is subject to time multiplexing withthe PUCCH or the PUSCH. For simplification of description, the DMRS isnot illustrated in FIG. 5.

FIG. 6 is a diagram illustrating an example of an arrangement ofphysical channels and physical signals in a special subframe of thepresent embodiment. In FIG. 6, the DwPTs is constituted by the first toninth SC-FDMA symbols of the special subframe, the GP is constituted bythe tenth to twelfth SC-FDMA symbols of the special subframe, and theUpPTS is constituted by the thirteenth and fourteenth SC-FDMA symbols ofthe special subframe.

The base station apparatus 3 may transmit the PCFICH, the PHICH, thePDCCH, the EPDCCH, the PDSCH, the synchronization signal, and thedownlink reference signal in the DwPTS of the special subframe. The basestation apparatus 3 does not transmit the PBCH in the DwPTS of thespecial subframe. The mobile station apparatus 1 may transmit the PRACHand the SRS in the UpPTS of the special subframe. In other words, themobile station apparatus 1 does not transmit the PUCCH, the PUSCH, andthe DMRS in the UpPTS of the special subframe.

Hereinafter, a first embodiment of the present invention will bedescribed.

FIG. 7 is a schematic block diagram illustrating a configuration of themobile station apparatus 1 according to the present embodiment. Asillustrated in FIG. 7, the mobile station apparatus 1 includes a higherlayer processing unit 101, a control unit 103, a reception unit 105, atransmission unit 107, and a transmit and receive antenna 109. Inaddition, the higher layer processing unit 101 includes a radio resourcecontrol portion 1011, a subframe setting portion 1013, and a schedulinginformation analysis portion 1015. Further, the reception unit 105includes a decoding portion 1051, a demodulation portion 1053, ademultiplexing portion 1055, a radio reception portion 1057, and achannel measurement portion 1059. Furthermore, the transmission unit 107includes a coding portion 1071, a modulation portion 1073, amultiplexing portion 1075, a radio transmission portion 1077, and anuplink reference signal generation portion 1079.

The higher layer processing unit 101 outputs uplink data (transportblock) which is generated through a user's operation or the like, to thetransmission unit 107. In addition, the higher layer processing unit 101performs processes on a medium access control (MAC) layer, a packet dataconvergence protocol (PDCP) layer, a radio link control (RLC) layer, anda radio resource control (RRC) layer.

The radio resource control portion 1011 of the higher layer processingunit 101 manages various items of setting information of the terminal.In addition, the radio resource control portion 1011 generatesinformation which is to be mapped in each channel of an uplink, andoutputs the information to the transmission unit 107.

The subframe setting portion 1013 of the higher layer processing unit101 manages an uplink reference configuration, a downlink referenceconfiguration, and a transmission direction configuration. The subframesetting portion 1013 sets the uplink reference configuration accordingto first information which is received via the reception unit 105 andindicates the uplink reference configuration, sets the downlinkreference configuration according to second information which isreceived via the reception unit 105 and indicates the downlink referenceconfiguration, and sets the transmission direction configurationaccording to third information which is received via the reception unit105 and indicates the transmission direction configuration. Hereinafter,the uplink reference configuration is also referred to as a firstconfiguration, the downlink reference configuration is also referred toas a second configuration, and the transmission direction configurationis also referred to as a third configuration.

The scheduling information analysis portion 1015 of the higher layerprocessing unit 101 analyzes a DCI format (scheduling information) whichis received via the reception unit 105, generates control informationfor controlling the reception unit 105 and the transmission unit 107 onthe basis of a result of analyzing the DCI format, and outputs thecontrol information to the control unit 103. The scheduling informationanalysis portion 1015 also determines timings for performing atransmission process and a reception process on the basis of the uplinkreference configuration, and/or the downlink reference configuration,and/or the transmission direction configuration.

The control unit 103 generates control signals for controlling thereception unit 105 and the transmission unit 107 on the basis of thecontrol information from the higher layer processing unit 101. Thecontrol unit 103 outputs the generated control signals to the receptionunit 105 and the transmission unit 107 so as to control the receptionunit 105 and the transmission unit 107.

The reception unit 105 demultiplexes, demodulates and decodes a receivedsignal which is received from the base station apparatus 3 via thetransmit and receive antenna 109, in response to the control signalwhich is input from the control unit 103, and outputs the decodedinformation to the higher layer processing unit 101.

The radio reception portion 1057 converts (down-converts) a downlinksignal which is received via the transmit and receive antenna 109 intoan intermediate frequency so as to remove unnecessary frequencycomponents, controls an amplification level so that a signal level isappropriately maintained, orthogonally demodulates the received signalon the basis of an in-phase component and an orthogonal componentthereof, and converts the orthogonally demodulated analog signal into adigital signal. The radio reception portion 1057 removes a portioncorresponding to a guard interval (GI) from the converted digitalsignal, and performs fast Fourier transform (FFT) on the signal fromwhich the guard interval is removed, so as to extract a signal of thefrequency domain.

The demultiplexing portion 1055 demultiplexes the extracted signal intothe PHICH, the PDCCH, the EPDCCH, the PDSCH, and the downlink referencesignal. Further, the demultiplexing portion 1055 compensates forchannels such as the PHICH, the PDCCH, the EPDCCH, and the PDSCH on thebasis of channel estimation values which are input from the channelmeasurement portion 1059. Furthermore, the demultiplexing portion 1055outputs the demultiplexed downlink reference signal to the channelmeasurement portion 1059.

The demodulation portion 1053 multiplies and combines the PHICH by andwith a corresponding sign, demodulates the combined signal in a binaryphase shift keying (BPSK) modulation method, and outputs an obtainedsignal to the decoding portion 1051. The decoding portion 1051 decodesthe PHICH directed to the mobile station apparatus, and outputs adecoded HARQ indicator to the higher layer processing unit 101. Thedemodulation portion 1053 demodulates the PDCCH and/or the EPDCCH in aQPSK modulation method, and outputs an obtained result to the decodingportion 1051. In a case where the decoding portion 1051 tries to decodethe PDCCH and/or the EPDCCH and succeeds in the decoding, and thedecoding portion outputs decoded downlink control information and RNTIcorresponding to the downlink control information to the higher layerprocessing unit 101.

The demodulation portion 1053 demodulates the PDSCH in a modulationmethod such as quadrature phase shift keying (QPSK), 16 quadratureamplitude modulation (QAM), or 64 QAM, of which a notification is sentin a downlink grant, and outputs an obtained result to the decodingportion 1051. The decoding portion 1051 performs decoding on the basisof information regarding a coding rate of which a notification has beensent with the downlink control information, and outputs decoded downlinkdata (transport block) to the higher layer processing unit 101.

The channel measurement portion 1059 measures a path loss of a downlinkor a channel state on the basis of the downlink reference signal whichis input from the demultiplexing portion 1055, and outputs the measuredpath loss or channel state to the higher layer processing unit 101. Inaddition, the channel measurement portion 1059 calculates a channelestimation value of the downlink on the basis of the downlink referencesignal, and outputs the estimation value to the demultiplexing portion1055.

The transmission unit 107 generates an uplink reference signal inresponse to the control signal which is input from the control unit 103,codes and modulates uplink data (transport block) which is input fromthe higher layer processing unit 101, multiplexes the PUCCH, the PUSCH,and the generated uplink reference signal, and transmits the obtainedresult to the base station apparatus 3 via the transmit and receiveantenna 109.

The coding portion 1071 performs coding such as convolutional coding orblock coding on the uplink control information which is input from thehigher layer processing unit 101. In addition, the coding portion 1071performs turbo coding on the basis of information used for schedulingthe PUSCH.

The modulation portion 1073 modulates the coded bits which are inputfrom the coding portion 1071 in a modulation method such as BPSK, QPSK,16 QAM, or 64 QAM, of which a notification is sent with the downlinkcontrol information, or in a modulation method which is predefined foreach channel. The modulation portion 1073 determines the number of datasequences which are spatially multiplexed on the basis of theinformation used for scheduling the PUSCH, maps a plurality of uplinkdata items which are transmitted in the same PUSCH to a plurality ofsequences by using multiple input multiple output spatial multiplexing(MIMO SM), and performs precoding on the sequences.

The uplink reference signal generation portion 1079 generates sequencesobtained according to a predefined rule (expression) on the basis of aphysical cell identity (PCI; referred to as a cell ID or the like) foridentifying the base station apparatus 3, a bandwidth in which theuplink reference signal is mapped, cyclic shift of which a notificationhas been sent in an uplink grant, values of parameters for generation ofa DMRS sequence, and the like. In response to the control signal whichis input from the control unit 103, the multiplexing portion 1075arranges modulation symbols of the PUSCH in parallel, and performsdiscrete Fourier transform (DFT) thereon. In addition, the multiplexingportion 1075 multiplexes signals of the PUCCH and the PUSCH, and thegenerated uplink reference signal for each transmit antenna port. Inother words, the multiplexing portion 1075 maps the signals of the PUCCHand the PUSCH and the generated uplink reference signal in resourceelements for each transmit antenna port.

The radio transmission portion 1077 performs inverse fast Fouriertransform (IFFT) on the multiplexed signal so as to perform modulationthereon in an SC-FDMA method; adds a guard interval to a SC-FDMA symbolwhich is SC-FDMA-modulated, so as to generate a digital signal with abase band; converts the digital signal with the base band into an analogsignal; generates an in-phase component and an orthogonal component withan intermediate frequency from the analog signal; removes a remainingfrequency component for an intermediate frequency band; converts(up-converts) the signal with the intermediate frequency into a signalwith a radio frequency; removes a remaining frequency componenttherefrom; amplifies power of the signal; and outputs the signal to thetransmit and receive antenna 109 so that the signal is transmitted.

FIG. 8 is a schematic block diagram illustrating a configuration of thebase station apparatus 3 of the present embodiment. As illustrated inFIG. 8, the base station apparatus 3 includes a higher layer processingunit 301, a control unit 303, a reception unit 305, a transmission unit307, and a transmit and receive antenna 309. In addition, the higherlayer processing unit 301 includes a radio resource control portion3011, a subframe setting portion 3013, and a scheduling portion 3015.Further, the reception unit 305 includes a decoding portion 3051, ademodulation portion 3053, a demultiplexing portion 3055, a radioreception portion 3057, and a channel measurement portion 3059.Furthermore, the transmission unit 307 includes a coding portion 3071, amodulation portion 3073, a multiplexing portion 3075, a radiotransmission portion 3077, and a downlink reference signal generationportion 3079.

The higher layer processing unit 301 performs processes on a mediumaccess control (MAC) layer, a packet data convergence protocol (PDCP)layer, a radio link control (RLC) layer, and a radio resource control(RRC) layer. In addition, the higher layer processing unit 301 generatescontrol information for controlling the reception unit 305 and thetransmission unit 307 and transmits the control information to thecontrol unit 303.

The radio resource control portion 3011 of the higher layer processingunit 301 generates downlink data (transport block) which will be mappedin the PDSCH of a downlink, system information, an RRC message, an MACcontrol element (CE), and the like, or acquires the information from ahigher node, and outputs the information to the transmission unit 307.In addition, the radio resource control portion 3011 manages variousitems of configuration information of each of the mobile stationapparatuses 1.

The subframe setting portion 3013 of the higher layer processing unit301 performs, on each of the mobile station apparatuses 1, management ofthe uplink reference configuration, the downlink referenceconfiguration, and the transmission direction configuration.

The subframe setting portion 3013 generates first information indicatingthe uplink reference configuration, second information indicating thedownlink reference configuration, and third information indicating thetransmission direction configuration. The subframe setting portion 3013transmits the first information, the second information, and the thirdinformation to the mobile station apparatus 1 via the transmission unit307.

The base station apparatus 3 may determine the uplink referenceconfiguration, the downlink reference configuration, and/or thetransmission direction configuration for the mobile station apparatus 1.In addition, the base station apparatus 3 may be given an instructionfor the uplink reference configuration, the downlink referenceconfiguration, and/or the transmission direction configuration, relatedto the mobile station apparatus 1, from a higher node.

For example, the subframe setting portion 3013 may determine the uplinkreference configuration, the downlink reference configuration, and/orthe transmission direction configuration on the basis of an uplinktraffic amount and a downlink traffic amount.

The scheduling portion 3015 of the higher layer processing unit 301determines a frequency and a subframe in which physical channels (thePDSCH and the PUSCH) are assigned, a coding rate of the physicalchannels (the PDSCH and the PUSCH), a modulation method, transmissionpower, and the like, on the basis of a channel estimation value, channelquality, or the like which is input from the channel measurement portion3059. The scheduling portion 3015 determines whether a downlink physicalchannel and/or a downlink physical signal (are) is scheduled or anuplink physical channel and/or an uplink physical signal (are) isscheduled, in a flexible subframe. The scheduling portion 3015 generatescontrol information (for example, a DCI format) for controlling thereception unit 305 and the transmission unit 307 on the basis of thescheduling result, and output the control information to the controlunit 303.

The scheduling portion 3015 generates information used for schedulingthe physical channels (the PDSCH and the PUSCH) on the basis of thescheduling result. The scheduling portion 3015 determines timings forperforming a transmission process and a reception process on the basisof the uplink reference configuration, the downlink referenceconfiguration, and/or the transmission direction configuration.

The control unit 303 generates control signals for controlling thereception unit 305 and the transmission unit 307 on the basis of thecontrol information from the higher layer processing unit 301. Thecontrol unit 303 outputs the generated control signals to the receptionunit 305 and the transmission unit 307 so as to control the receptionunit 305 and the transmission unit 307.

The reception unit 305 demultiplexes, demodulates and decodes a receivedsignal which is received from the mobile station apparatus 1 via thetransmit and receive antenna 309, in response to the control signalwhich is input from the control unit 303, and outputs the decodedinformation to the higher layer processing unit 301. The radio receptionportion 3057 converts (down-converts) an uplink signal which is receivedvia the transmit and receive antenna 309 into an intermediate frequencyso as to remove unnecessary frequency components, controls anamplification level so that a signal level is appropriately maintained,orthogonally demodulates the received signal on the basis of an in-phasecomponent and an orthogonal component thereof, and converts theorthogonally demodulated analog signal into a digital signal.

The radio reception portion 3057 removes a portion corresponding to aguard interval (GI) from the converted digital signal. The radioreception portion 3057 performs fast Fourier transform (FFT) on thesignal from which the guard interval is removed, so as to extract asignal of the frequency domain which is thus output to thedemultiplexing portion 3055.

The demultiplexing portion 1055 demultiplexes the signal which is inputfrom the radio reception portion 3057, into signals such as the PUCCH,the PUSCH, and the uplink reference signal. In addition, thisdemultiplexing is performed on the basis of radio resource assignmentinformation which is determined in advance by the radio resource controlportion 3011 and is included in an uplink grant of which the basestation apparatus 3 notifies each mobile station apparatus 1. Further,the demultiplexing portion 3055 compensates channels such as the PUCCHand the PUSCH on the basis of channel estimation values which are inputfrom the channel measurement portion 3059. Furthermore, thedemultiplexing portion 3055 outputs the demultiplexed uplink referencesignal to the channel measurement portion 3059.

The demodulation portion 3053 performs inverse discrete Fouriertransform (IDFT) on the PUSCH so as to acquire modulation symbols, andperforms demodulation of the received signal on each of modulationsymbols of the PUCCH and the PUSCH, by using a modulation method whichis predefined, such as binary phase shift keying (BPSK), quadraturephase shift keying (QPSK), 16 QAM, or 64 QAM, or a modulation method ofwhich the base station apparatus 3 notifies the mobile station apparatus1 in advance in an uplink grant. The demodulation portion 3053demultiplexes modulation symbols of a plurality of uplink data itemstransmitted in the same PUSCH by using the MIMO SM on the basis of thenumber of spatially multiplexed sequences of which a notification issent to each mobile station apparatus 1 in advance in the uplink grantand information for giving an instruction for precoding which will beperformed on the sequences.

The decoding portion 3051 decodes coded bits of the demodulated PUCCHand PUSCH at a coding rate which is predefined in a predefined codingmethod or of which the base station apparatus 3 notifies the mobilestation apparatus 1 in the uplink grant in advance, and outputs decodeduplink data and uplink control information to the higher layerprocessing unit 101. In a case where the PUSCH is retransmitted, thedecoding portion 3051 performs decoding by using coded bits which areinput from the higher layer processing unit 301 and are stored in a HARQbuffer and the demodulated coded bits. The channel measurement portion309 measures channel estimation values, quality of the channels, and thelike on the basis of the uplink reference signal which is input from thedemultiplexing portion 3055, and outputs the measured results to thedemultiplexing portion 3055 and the higher layer processing unit 301.

The transmission unit 307 generates a downlink reference signal inresponse to the control signal which is input from the control unit 303,codes and modulates the HARQ indicator, the downlink control signal, andthe downlink data which are input from the higher layer processing unit301, multiplexes the PHICH, the PDCCH, the EPDCCH, the PDSCH, and thedownlink reference signal, and transmits a signal to the mobile stationapparatus 1 via the transmit and receive antenna 309.

The coding portion 3071 performs coding on the HARQ indicator, thedownlink control information, and the downlink data which are input fromthe higher layer processing unit 301, by using a predefined codingmethod such as block coding, convolutional coding, or turbo coding, orby using a coding method determined by the radio resource controlportion 3011. The modulation portion 3073 modulates the coded bits whichare input from the coding portion 3071 by using a predefined modulationmethod such as BPSK, QPSK, 16 QAM, or 64 QAM, or by using a modulationmethod determined by the radio resource control portion 3011.

The downlink reference signal generation portion 3079 generatessequences which are obtained in a predefined rule and are known to themobile station apparatus 1, as the downlink reference signal, on thebasis of a physical cell identity (PCI) or the like for identifying thebase station apparatus 3. The multiplexing portion 3075 multiplexes themodulation symbol of each modulated channel and the generated downlinkreference signal. In other words, the multiplexing portion 3075 maps themodulation symbol of each modulated channel and the generated downlinkreference signal in resource elements.

The radio transmission portion 3077 performs inverse fast Fouriertransform (IFFT) on the multiplexed modulation symbol so as to performmodulation thereon in an OFDM method; adds a guard interval to an OFDMsymbol which is OFDM-modulated, so as to generate a digital signal witha base band; converts the digital signal with the base band into ananalog signal; generates an in-phase component and an orthogonalcomponent with an intermediate frequency from the analog signal; removesa remaining frequency component for an intermediate frequency band;converts (up-converts) the signal with the intermediate frequency into asignal with a radio frequency (RF); removes a remaining frequencycomponent therefrom; amplifies power of the signal; and outputs thesignal to the transmit and receive antenna 309 so that the signal istransmitted.

The downlink reference configuration, the uplink referenceconfiguration, and the transmission direction configuration are definedby an uplink-downlink configuration (UL-DL configuration). Theuplink-downlink configuration is a configuration related to a pattern ofsubframes of a radio frame. In other words, the downlink referenceconfiguration, the uplink reference configuration, and the transmissiondirection configuration are defined by patterns of the downlinksubframe, the uplink subframe, and the special subframe of the radioframe.

The uplink reference configuration is also referred to as an uplinkreference uplink-downlink configuration (uplink reference UL-DLconfiguration) or a first parameter. The downlink referenceconfiguration is also referred to as a downlink referenceuplink-downlink configuration (downlink reference UL-DL configuration)or a second parameter. The transmission direction configuration is alsoreferred to as a transmission direction uplink-downlink configuration(transmission direction UL-DL configuration) or a third parameter.

FIG. 9 is a table illustrating an example of an uplink-downlinkconfiguration in the present embodiment. In FIG. 9, D indicates adownlink subframe, U indicates an uplink subframe, and S indicates aspecial subframe.

In FIG. 9, a subframe 1 of the radio frame is a special subframe at alltimes. In FIG. 9, subframes 0 and 5 are reserved for downlinktransmission at all times, and the subframe 1 is a special subframe atall times.

In FIG. 9, in a case where the downlink-to-uplink switch-pointperiodicity is 5 ms, a subframe 6 of the radio frame is a specialsubframe. In a case where the downlink-to-uplink switch-pointperiodicity is 10 ms, the subframe 6 of the radio frame is a downlinksubframe.

An uplink-downlink configuration i being set as the uplink referenceconfiguration is referred to as an uplink reference configuration ibeing set. An uplink-downlink configuration i being set as the downlinkreference configuration is referred to as a downlink referenceconfiguration i being set. An uplink-downlink configuration i being setas the transmission direction configuration is referred to as atransmission direction configuration i being set.

The base station apparatus 3 may transmit first information (TDD-Config)indicating the uplink reference configuration, second informationindicating the downlink reference configuration, and third informationindicating the transmission direction configuration, which include atleast one of an MIB, a system information block type 1 message, a systeminformation message, an RRC message, an MAC control element (CE), andcontrol information (for example, a DCI format) of a physical layer. Inaddition, the base station apparatus 3 may include the firstinformation, the second information, and the third information in atleast one of the MIB, the system information block type 1 message, thesystem information message, the RRC message, the MAC control element(CE), and the control information (for example, a DCI format) of aphysical layer, depending on circumstances.

The mobile station apparatus 1 receives the first information, thesecond information, and the third information. The mobile stationapparatus 1 sets an uplink-downlink configuration indicated by thereceived first information as an uplink reference configuration. Themobile station apparatus 1 sets an uplink-downlink configurationindicated by the received second information as a downlink referenceconfiguration. The mobile station apparatus 1 sets an uplink-downlinkconfiguration indicated by the received third information as atransmission direction configuration. The first information is alsoreferred to as a first parameter. The second information is alsoreferred to as a second parameter. The third information is alsoreferred to as a third parameter.

In addition, the mobile station apparatus 1 for which two cells are setmay receive the first information for a certain cell and the firstinformation for the other cell. Further, the mobile station apparatus 1for which two cells may determine an uplink reference configuration fora certain cell on the basis of an uplink-downlink configuration isindicated by the first information for the certain cell and anuplink-downlink configuration indicated by the first information for theother cell.

Still further, the mobile station apparatus 1 for which two cells areset may determine a downlink reference configuration for a certain cellon the basis of an uplink-downlink configuration indicated by the secondinformation for the certain cell and an uplink-downlink configurationindicated by the second information for the other cell.

Furthermore, the mobile station apparatus 1 for which two cells are setmay determine a downlink reference configuration for a certain cell onthe basis of an uplink-downlink configuration indicated by the firstinformation for the certain cell and an uplink-downlink configurationindicated by the second information for the other cell.

Moreover, the mobile station apparatus 1 for which two cells are set maydetermine a downlink reference configuration for a certain cell on thebasis of an uplink-downlink configuration indicated by the secondinformation for the certain cell and an uplink-downlink configurationindicated by the first information for the other cell.

The first information indicating an uplink reference configuration ispreferably included in the system information block type 1 message. Thesecond information indicating a downlink reference configuration ispreferably included in the system information block type 1 message, thesystem information message, or the RRC message. The third informationindicating a transmission direction configuration is preferably includedin the MIB, the MAC CE, or the control information (for example, a DCIformat) of a physical layer.

The first information indicating an uplink reference configuration ispreferably common to a plurality of mobile station apparatuses 1 in acell. The second information indicating a downlink referenceconfiguration may be common to the plurality of mobile stationapparatuses 1 in the cell, and may be dedicated to the mobile stationapparatus 1. The third information may be common to the plurality ofmobile station apparatuses 1 in the cell, and may be dedicated to themobile station apparatus 1.

The second information indicating a downlink reference configuration maybe transmitted along with the first information indicating an uplinkreference configuration. The mobile station apparatus 1 in which adownlink reference configuration is not set may not receive the thirdinformation indicating a transmission direction configuration.

The periodicity of changing the transmission direction configuration ispreferably shorter than the periodicity of changing the downlinkreference configuration. A frequency of changing the transmissiondirection configuration is preferably lower than a frequency of changingthe downlink reference configuration. The periodicity of changing thedownlink reference configuration is preferably shorter than theperiodicity of changing the uplink reference configuration. A frequencyof changing the downlink reference configuration is preferably lowerthan a frequency of changing the uplink reference configuration.

The system information block type 1 message is transmitted in thesubframe 5 of the radio frame satisfying SFN mod 2=0, via a PDSCH. Thesystem information block type 1 message includes information indicatinga configuration (lengths of a DwPTS, a GP, and a UpPTS) of a specialsubframe. The system information block type 1 message is cell-specificinformation.

The system information message is transmitted via the PDSCH. The systeminformation message is cell-specific information. The system informationmessage includes system information blocks other than the systeminformation block type 1 message.

The RRC message is transmitted via the PDSCH. The RRC message isinformation/signal which is processed in an RRC layer. The RRC messagemay be dedicated to a specified mobile station apparatus 1.

The MAC CE is transmitted via the PDSCH. The MAC CE isinformation/signal which is processed in an MAC layer.

In a case where an RRC message including the first information/thesecond information, and/or the third information are (is) received viathe PDSCH, the mobile station apparatus 1 preferably sets (makes valid)the uplink reference configuration/the downlink reference configuration,and/or the transmission direction configuration in a subframe (timing)in which an “RRC connection reconfiguration completion message”corresponding to the RRC message is transmitted.

In a case where an MIB including the first information/the secondinformation, and/or the third information is received via a PBCH in asubframe n−k, the mobile station apparatus 1 preferably sets (makesvalid) the uplink reference configuration/the downlink referenceconfiguration, and/or the transmission direction configuration in asubframe n. For example, k is 4. For example, k is determined on thebasis of a table of FIG. 13 and the uplink-downlink configuration/thedownlink reference configuration. FIG. 13 will be described later.

In a case where an MAC CE including the first information/the secondinformation, and/or the third information is received via a PDSCH in asubframe n−k, the mobile station apparatus 1 preferably sets (makesvalid) the uplink reference configuration/the downlink referenceconfiguration, and/or the transmission direction configuration in asubframe n. For example, k is 4. For example, a subframe n+k is asubframe for transmitting a HARQ-ACK (ACK) of the PDSCH which is used totransmit the MAC CE. For example, k is determined on the basis of thetable of FIG. 13 and the uplink reference configuration/the downlinkreference configuration.

In a case where control information (for example, a DCI format) of aphysical layer including the first information/the second information,and/or the third information is received via a downlink physical channel(for example, a PDCCH/EPDCCH) in a subframe n−k, the mobile stationapparatus 1 preferably sets (makes valid) the uplink referenceconfiguration/the downlink reference configuration, and/or thetransmission direction configuration in a subframe n. For example, k is4. For example, a subframe n+k is a subframe for transmitting a HARQ-ACK(ACK) of the downlink physical channel (for example, a PDCCH/EPDCCH)which is used to transmit the control information (for example, a DCIformat) of the physical layer. For example, k is determined on the basisof the table of FIG. 13 and the uplink reference configuration/thedownlink reference configuration.

Hereinafter, unless otherwise described, the mobile station apparatus 1in which the uplink reference configuration, the downlink referenceconfiguration, and the transmission direction configuration are set isreferred to as a mobile station apparatus 1.

Hereinafter, the uplink reference configuration will be described indetail.

The uplink reference configuration is used to specify (select,determine) a correspondence between a subframe n in which thePDCCH/EPDCCH/PHICH is allocated and a subframe n+k in which the PUSCHcorresponding to the PDCCH/EPDCCH/PHICH is allocated.

FIG. 10 is a diagram illustrating a correspondence between the subframen in which the PDCCH/EPDCCH/PHICH is allocated and the subframe n+k inwhich the PUSCH corresponding to the PDCCH/EPDCCH/PHICH is allocated inthe present embodiment. The mobile station apparatus 1 specifies(selects, determines) a value of k on the basis of a table of FIG. 10.

In a case where the mobile station apparatus 1 in which uplink referenceconfigurations 1 to 6 are set detects the PDCCH/EPDCCH which includes anuplink grant intended for the mobile station apparatus 1 in the subframen, the PUSCH corresponding to the uplink grant is transmitted in thesubframe n+k which is specified (selected, determined) on the basis ofthe table of FIG. 10.

In a case where the mobile station apparatus 1 in which the uplinkreference configurations 1 to 6 are set detects the PHICH intended forthe mobile station apparatus 1 in the subframe n, the PUSCHcorresponding to the PHICH is transmitted in the subframe n+k which isspecified (selected, determined) on the basis of the table of FIG. 10.

An uplink grant intended for the mobile station apparatus 1 in which theuplink reference configuration 0 is set includes a 2-bit uplink index(UL index). An uplink grant intended for the mobile station apparatus 1in which the uplink reference configurations 1 to 6 are set does notinclude the uplink index (UL index).

In a case where 1 is set to a most significant bit (MSB) of an uplinkindex included in the uplink grant in the subframe n, the mobile stationapparatus 1 in which the uplink reference configuration 0 is set adjuststransmission of the PUSCH corresponding to the uplink grant in thesubframe n+k which is specified (selected, determined) on the basis ofthe table of FIG. 10.

In a case where the mobile station apparatus 1 in which the uplinkreference configuration 0 is set receives a PHICH in a first resourceset of the subframe n=0 or 5, the mobile station apparatus adjuststransmission of the PUSCH corresponding to the PHICH in the subframe n+kwhich is specified (selected, determined) on the basis of the table ofFIG. 10.

In a case where 1 is set to a least significant bit (LSB) of an uplinkindex included in the uplink grant in the subframe n, the mobile stationapparatus 1 in which the uplink reference configuration 0 is set adjuststransmission of the PUSCH corresponding to the uplink grant in thesubframe n+7.

In a case where the mobile station apparatus 1 in which the uplinkreference configuration 0 is set receives a PHICH in a second resourceset of the subframe n=0 or 5, or receives the PHICH in the subframe n=1or 6, the mobile station apparatus adjusts transmission of the PUSCHcorresponding to the uplink grant in the subframe n+7.

In a case where the mobile station apparatus 1 in which the uplinkreference configuration 1 is set detects PDCCH/EPDCCH/PHICH in [SFN=m,subframe 1], the mobile station apparatus adjusts transmission of thePUSCH in [SFN=m, subframe 7] which is six subframes later than thesubframe 1.

The uplink reference configuration is used to specify (select,determine) a correspondence between the subframe n in which the PHICH isallocated and the subframe n−k in which the PUSCH corresponding to thePHICH is allocated.

FIG. 11 is a diagram illustrating a correspondence between the subframen in which the PHICH is allocated and the subframe n−k in which thePUSCH corresponding to the PHICH is allocated in the present embodiment.The mobile station apparatus 1 specifies (selects, determines) a valueof k on the basis of a table of FIG. 11.

In a case where the uplink-downlink configurations 1 to 6 are set in themobile station apparatus 1, a HARQ indicator (HARQ-ACK) which isreceived via a PHICH assigned to the mobile station apparatus 1 in thesubframe n is related to transmission of a PUSCH in the subframe n−kwhich is specified on the basis of the table of FIG. 11.

In a case where the uplink reference configuration 0 is set in themobile station apparatus 1, a HARQ indicator (HARQ-ACK) which isreceived via a PHICH assigned to the mobile station apparatus 1 in afirst resource set of the subframe n=0 or 5, or in the subframes n=1 or6, is related to transmission of a PUSCH in the subframe n−k which isspecified on the basis of the table of FIG. 11.

In a case where the uplink reference configuration 0 is set in themobile station apparatus 1, a HARQ indicator (HARQ-ACK) which isreceived via a PHICH assigned to the mobile station apparatus 1 in asecond resource set of the subframe n=0 or 5 is related to thetransmission of a PUSCH in the subframe n−6.

For example, regarding the mobile station apparatus 1 in which theuplink reference configuration 1 is set, a HARQ indicator (HARQ-ACK)which is received via the PHICH in [SFN=m, subframe 1] is related totransmission of the PUSCH in [SFN=m−1, subframe 7] which is foursubframes earlier than the subframe 1.

The uplink reference configuration is used to specify (select,determine) a correspondence between the subframe n in which a PUSCH isallocated and the subframe n+k in which a PHICH corresponding to thePUSCH is allocated.

FIG. 12 is a diagram illustrating a correspondence between the subframen in which the PUSCH is allocated and the subframe n+k in which thePHICH corresponding to the PUSCH is allocated in the present embodiment.The mobile station apparatus 1 specifies (selects, determines) a valueof k on the basis of a table of FIG. 12.

In a case where transmission of the PUSCH is scheduled in the subframen, the mobile station apparatus 1 determines a PHICH resource in thesubframe n+k which is specified on the basis of the table of FIG. 12.

For example, regarding the mobile station apparatus 1 in which theuplink reference configuration 0 is set, in a case where transmission ofthe PUSCH is scheduled in [SFN=m, subframe n=2], a PHICH resource isdetermined in [SFN=m, subframe n=6].

For example, regarding the mobile station apparatus 1 in which theuplink reference configuration 0 is set, in a case where transmission ofthe PUSCH is scheduled in [SFN=m, subframe n=3], a PHICH resource isdetermined from a first resource set in [SFN=m+1, subframe n=0].

For example, regarding the mobile station apparatus 1 in which theuplink reference configuration 0 is set, in a case where transmission ofthe PUSCH is scheduled in [SFN=m, subframe n=4], a PHICH resource isdetermined from a second resource set in [SFN=m+1, subframe n=0].

For example, regarding the mobile station apparatus 1 in which theuplink reference configuration 0 is set, in a case where transmission ofthe PUSCH is scheduled in [SFN=m, subframe n=7], a PHICH resource isdetermined in [SFN=m+1, subframe n=1].

For example, regarding the mobile station apparatus 1 in which theuplink reference configuration 0 is set, in a case where transmission ofthe PUSCH is scheduled in [SFN=m, subframe n=8], a PHICH resource isdetermined from a first resource set in [SFN=m+1, subframe n=5].

For example, regarding the mobile station apparatus 1 in which theuplink reference configuration 0 is set, in a case where transmission ofthe PUSCH is scheduled in [SFN=m, subframe n=9], a PHICH resource isdetermined from a second resource set in [SFN=m+1, subframe n=5].

Hereinafter, the downlink reference configuration will be described indetail.

The downlink reference configuration is used to specify (select,determine) a correspondence between the subframe n in which a PDSCH isallocated and the subframe n+k in which a HARQ-ACK corresponding to thePDSCH is transmitted.

FIG. 13 is a diagram illustrating a correspondence between the subframen−k in which the PDSCH is allocated and the subframe n in which aHARQ-ACK corresponding to the PDSCH is transmitted in the presentembodiment. The mobile station apparatus 1 specifies (selects,determines) a value of k on the basis of a table of FIG. 13.

In a case where the mobile station apparatus 1 detects, in a subframen−k (k is specified on the basis of the table of FIG. 13) for a servingcell, transmission of the PDSCH intended for the mobile stationapparatus 1 and for which a corresponding HARQ-ACK shall be transmitted,the HARQ-ACK is transmitted in the subframe n.

For example, the mobile station apparatus 1 does not make a response ofthe HARQ-ACK to transmission of the PDSCH which is used to transmitsystem information. For example, the mobile station apparatus 1 makes aresponse of the HARQ-ACK to transmission of the PDSCH which is scheduledby a DCI format including the CRC scrambled with the C-RNTI.

For example, the mobile station apparatus 1 in which the uplinkreference configuration 1 is set performs transmission of the HARQ-ACKof the PDSCH received in the subframe n−6 and/or n−7 in the subframen=2.

Further, the mobile station apparatus 1 in which the uplink referenceconfiguration is set and the downlink reference configuration is not setmay specify (select, determine) a correspondence between the subframen−k in which a PDSCH is allocated and the subframe n in which a HARQ-ACKcorresponding to the PDSCH is transmitted, according to the uplinkreference configuration.

In addition, the mobile station apparatus 1 in which the uplinkreference configuration is set and the downlink reference configurationis not set may determine the timings (subframes) at which downlinkreception and uplink transmission are performed, according to the uplinkreference configuration. The mobile station apparatus 1 in which thedownlink reference configuration is not set may disregard the thirdinformation indicating a transmission direction configuration.

In addition, the mobile station apparatus 1 which has received the firstinformation and has not received the second information may set thedownlink reference configuration therein on the basis of the firstinformation. The mobile station apparatus 1 which sets the downlinkreference configuration therein on the basis of the first informationmay disregard the third information indicating a transmission directionconfiguration.

The mobile station apparatus 1 which sets the downlink referenceconfiguration therein on the basis of the first information is alsoreferred to as a mobile station apparatus 1 in which the dynamic TDD isnot set. The mobile station apparatus 1 which sets the downlinkreference configuration therein on the basis of the second informationis also referred to as a mobile station apparatus 1 in which the dynamicTDD is set.

The mobile station apparatus 1 which sets the uplink referenceconfiguration on the basis of the first information may perform ameasurement (for example, a measurement regarding channel stateinformation) using a downlink signal in a downlink subframe or a DwPTSof a special subframe which is indicated by the uplink referenceconfiguration.

Therefore, in the dynamic TDD, if the base station apparatus 3 uses asubframe which is indicated as a downlink subframe by the uplinkreference configuration, as a special subframe or an uplink subframe, oruses a subframe which is indicated as a special subframe by the uplinkreference configuration, as an uplink subframe, there is a problem inthat the mobile station apparatus 1 in which the t downlink referenceconfiguration is set on the basis of the first information, cannotappropriately perform the measurement using a downlink signal.

Thus, the base station apparatus 3 determines a downlink referenceconfiguration from a configuration set (configurations of the set) whichis restricted on the basis of the uplink reference configuration. Inother words, the downlink reference configuration is an element of theconfiguration set which is restricted on the basis of the uplinkreference configuration. The configuration set restricted on the basisof the uplink reference configuration includes uplink-downlinkconfigurations which satisfy the following conditions (a) to (c). FIG.14 is a diagram of the relationship between a subframe indicated by theuplink reference configuration and a subframe indicated by the downlinkreference configuration in a first embodiment of the present invention.In FIG. 14, D indicates a downlink subframe, U indicates an uplinksubframe, and S indicates a special subframe.

(a) a subframe which is indicated as a downlink subframe by the uplinkreference configuration is indicated as a downlink subframe

(b) a subframe which is indicated as an uplink subframe by the uplinkreference configuration is indicated as an uplink subframe or a downlinksubframe

(c) a subframe which is indicated as a special subframe by the uplinkreference configuration is indicated as a downlink subframe or a specialsubframe

Consequently, in the dynamic TDD, since a subframe which is indicated asa downlink subframe by the uplink reference configuration, and a DwPTSof a special subframe are not used for uplink transmission, the mobilestation apparatus 1 in which the downlink reference configuration is seton the basis of the first information can appropriately perform ameasurement using a downlink signal.

In addition, the mobile station apparatus 1 for which the downlinkreference configuration is set on the basis of the second informationmay also perform a measurement (for example, a measurement regardingchannel state information) using a downlink signal in a downlinksubframe or a DwPTS of a special subframe indicated by the uplinkreference configuration.

The base station apparatus 3 may perform scheduling of downlinktransmission in a subframe which is indicated as a downlink subframe bythe uplink reference configuration and the downlink referenceconfiguration.

The base station apparatus 3 may perform scheduling of uplinktransmission in a subframe which is indicated as an uplink subframe bythe uplink reference configuration and the downlink referenceconfiguration.

The base station apparatus 3 may perform scheduling of uplinktransmission or downlink transmission in a subframe which is indicatedas an uplink subframe by the uplink reference configuration and isindicated as a downlink subframe by the downlink referenceconfiguration.

In other words, the base station apparatus 3 may use, as an uplinksubframe or a downlink subframe, a subframe which is indicated as anuplink subframe by the uplink reference configuration and is indicatedas a downlink subframe by the downlink reference configuration.

The base station apparatus 3 may perform scheduling of downlinktransmission in a DwPTS of a subframe which is indicated as a specialsubframe by the uplink reference configuration and the downlinkreference configuration.

The base station apparatus 3 may perform scheduling of uplinktransmission in a UpPTS of a subframe which is indicated as a specialsubframe by the uplink reference configuration and the downlinkreference configuration.

The base station apparatus 3 may perform scheduling of downlinktransmission in a DwPTS of a subframe which is indicated as a specialsubframe by the uplink reference configuration and is indicated as adownlink by the downlink reference configuration.

The base station apparatus 3 may perform scheduling of uplinktransmission in a UpPTS of a subframe which is indicated as a specialsubframe by the uplink reference configuration and is indicated as adownlink subframe by the downlink reference configuration.

The base station apparatus 3 may perform scheduling of downlinktransmission in a subframe which is indicated as a special subframe bythe uplink reference configuration and is indicated as a downlink by thedownlink reference configuration.

In other words, the base station apparatus 3 may use, as a downlinksubframe, a subframe which is indicated as a special subframe by theuplink reference configuration and is indicated as a downlink by thedownlink reference configuration.

A subframe which is indicated as a special subframe by the uplinkreference configuration and is indicated as a downlink subframe by thedownlink reference configuration, and a subframe which is indicated as aspecial subframe by the uplink reference configuration and is indicatedas a downlink subframe by the downlink reference configuration, are alsoreferred to as flexible subframes.

Hereinafter, the transmission direction configuration will be describedin detail.

If the mobile station apparatus 1 determines a transmission direction(up/down) on the basis of the uplink reference configuration, thedownlink reference configuration, and scheduling information (a DCIformat and/or a HARQ-ACK), there is a problem in that the mobile stationapparatus 1 which erroneously receives/decodes the schedulinginformation (a DCI format and/or a HARQ-ACK) transmits an uplink signalin a subframe in which the base station apparatus 3 transmits a downlinksignal to other mobile station apparatuses 1, and thus the uplink signalinterferes with the downlink signal.

Therefore, the mobile station apparatus 1 of the present invention setsthe transmission direction configuration regarding a transmissiondirection (up/down) in a subframe. The transmission directionconfiguration is used to determine a transmission direction in asubframe.

The base station apparatus 3 transmits the third information indicatingthe transmission direction configuration to the mobile station apparatus1. The third information is information indicating a subframe in whichuplink transmission can be performed. The third information isinformation indicating a subframe in which downlink transmission can beperformed. The third information is information indicating a subframe inwhich uplink transmission in the UpPTS and downlink transmission in theDwPTS can be performed.

For example, the transmission direction configuration is used to specifya transmission direction in a subframe which is indicated as an uplinksubframe by the uplink reference configuration and is indicated as adownlink subframe by the downlink reference configuration, and/or asubframe which is indicated as a special subframe by the uplinkreference configuration and is indicated as a downlink subframe by thedownlink reference configuration. In other words, the transmissiondirection configuration is used to specify a transmission direction in asubframe which is indicated as a subframe which is different from asubframe which is indicated by the uplink reference configuration andthe downlink reference configuration.

FIG. 15 is a diagram illustrating the relationship between a subframeindicated by the uplink reference configuration, a subframe indicated bythe downlink reference configuration, and a subframe indicated by thetransmission direction configuration in the first embodiment of thepresent invention. In FIG. 15, D indicates a downlink subframe, Uindicates an uplink subframe, and S indicates a special subframe.

The base station apparatus 3 determines the transmission directionconfiguration from a configuration set (configurations of the set) whichis restricted on the basis of the uplink reference configuration and thedownlink reference configuration. In other words, the transmissiondirection configuration is an element of the configuration set which isrestricted on the basis of the uplink reference configuration and thedownlink reference configuration. The configuration set which isrestricted on the basis of the uplink reference configuration and thedownlink reference configuration includes uplink-downlink configurationswhich satisfy the following conditions (d) to (h).

(d) a subframe which is indicated as a downlink subframe by the uplinkreference configuration and the downlink reference configuration isindicated as a downlink subframe

(e) a subframe which is indicated as an uplink subframe by the uplinkreference configuration and the downlink reference configuration isindicated as an uplink subframe

(f) a subframe which is indicated as an uplink subframe by the uplinkreference configuration but is indicated as a downlink subframe by thedownlink reference configuration is indicated as an uplink subframe or adownlink subframe

(g) a subframe which is indicated as a special subframe by the uplinkreference configuration and the downlink reference configuration isindicated as a special subframe

(h) a subframe which is indicated as a special subframe by the uplinkreference configuration but is indicated as a downlink subframe by thedownlink reference configuration is indicated as a special subframe or adownlink subframe

The base station apparatus 3 may perform scheduling of downlinktransmission in a subframe which is indicated as a downlink subframe bythe transmission direction configuration.

The mobile station apparatus 1 may perform a reception process of adownlink signal in a subframe which is indicated as a downlink subframeby the transmission direction configuration. The mobile stationapparatus 1 may perform monitoring of the PDCCH/EPDCCH in a subframewhich is indicated as a downlink subframe by the transmission directionconfiguration. In a case where the mobile station apparatus 1 detects adownlink grant via the PDCCH/EPDCCH in a subframe which is indicated asa downlink subframe by the transmission direction configuration, themobile station apparatus may perform a reception process of a PDSCHcorresponding to the downlink grant in the subframe.

In a case where transmission of an uplink signal (PUSCH/SRS) in asubframe indicated as a downlink subframe by the transmission directionconfiguration is scheduled by using downlink control information whichis received via the PDCCH/EPDCCH, the mobile station apparatus 1 doesnot perform a transmission process of the uplink signal (PUSCH/SRS) inthe subframe.

The base station apparatus 3 may perform scheduling of uplinktransmission in a subframe which is indicated as an uplink subframe bythe transmission direction configuration.

The base station apparatus 3 may perform scheduling of downlinktransmission in a subframe which is indicated as an uplink subframe bythe transmission direction configuration. The base station apparatus 3may be prohibited from performing scheduling of downlink transmission ina subframe which is indicated as an uplink subframe by the transmissiondirection configuration.

The mobile station apparatus 1 may perform a transmission process of anuplink signal in a subframe which is indicated as an uplink subframe bythe transmission direction configuration. The mobile station apparatus 1may perform a transmission process of PUSCH/DMRS/SRS in a subframe whichis indicated as an uplink subframe by the transmission directionconfiguration. In a case where transmission of the uplink signal(PUSCH/SRS) in a subframe indicated as an uplink subframe by thetransmission direction configuration is scheduled by downlink controlinformation received via the PDCCH/EPDCCH, the mobile station apparatus1 may perform a transmission process of the uplink signal (PUSCH/SRS) inthe subframe.

The mobile station apparatus 1 may perform a reception process of adownlink signal in a subframe which is indicated as an uplink subframeby the transmission direction configuration and in which uplinktransmission is not scheduled. The mobile station apparatus 1 may beprohibited from performing a reception process of a downlink signal in asubframe which is indicated as an uplink subframe by the transmissiondirection configuration.

The base station apparatus 3 performs scheduling of downlinktransmission in a DwPTS of a subframe which is indicated as a specialsubframe by the transmission direction configuration.

The mobile station apparatus 1 may perform a reception process of adownlink signal in a DwPTS of a subframe which is indicated as a specialsubframe by the transmission direction configuration. The mobile stationapparatus 1 may perform monitoring of the PDCCH/EPDCCH in a DwPTS of asubframe which is indicated as a special subframe by the transmissiondirection configuration. In a case where the mobile station apparatus 1detects a downlink grant via the PDCCH/EPDCCH in a DwPTS of a subframewhich is indicated as a special subframe by the transmission directionconfiguration, the mobile station apparatus may perform a receptionprocess of a PDSCH corresponding to the downlink grant in the DwPTS ofthe subframe.

In a case where transmission of a PUSCH in a subframe indicated as aspecial subframe by the transmission direction configuration isscheduled by downlink control information received via the PDCCH/EPDCCH,the mobile station apparatus 1 does not perform a transmission processof the PUSCH in the subframe.

In a case where transmission of an SRS in a UpPTS of a subframeindicated as a special subframe by the transmission directionconfiguration is scheduled by downlink control information received viathe PDCCH/EPDCCH, the mobile station apparatus 1 may perform atransmission process of the SRS in the UpPTS of the subframe.

FIG. 16 is a diagram illustrating a relationship between the uplinkreference configuration, the downlink reference configuration, and thetransmission direction configuration, in the first embodiment of thepresent invention.

In FIG. 16, in a case where an uplink-downlink configuration of theuplink reference configuration is 0, the downlink referenceconfiguration is one of the uplink-downlink configuration set {0, 1, 2,3, 4, 5, 6,}.

In FIG. 16, in a case where an uplink-downlink configuration of theuplink reference configuration is 1, the downlink referenceconfiguration is one of the uplink-downlink configuration set {2, 4, 5}.

In FIG. 16, in a case where an uplink-downlink configuration of theuplink reference configuration is 2, the downlink referenceconfiguration is the uplink-downlink configuration set {5}. In otherwords, in a case where an uplink-downlink configuration of the uplinkreference configuration is 2, the downlink reference configuration isthe uplink-downlink configuration 5.

In FIG. 16, in a case where an uplink-downlink configuration of theuplink reference configuration is 3, the downlink referenceconfiguration is one of the uplink-downlink configuration set {4, 5}.

In FIG. 16, in a case where an uplink-downlink configuration of theuplink reference configuration is 4, the downlink referenceconfiguration is the uplink-downlink configuration set {5}. In otherwords, in a case where an uplink-downlink configuration of the uplinkreference configuration is 4, the downlink reference configuration isthe uplink-downlink configuration 5.

In FIG. 16, in a case where an uplink-downlink configuration of theuplink reference configuration is 5, the downlink referenceconfiguration and the transmission direction configuration are not set.

In FIG. 16, in a case where an uplink-downlink configuration of theuplink reference configuration is 0, the downlink referenceconfiguration is one of the uplink-downlink configuration set {0, 1, 2,3, 4, 5}.

For example, in FIG. 16, in a case where an uplink-downlinkconfiguration of the uplink reference configuration is 0 and anuplink-downlink configuration of the downlink reference configuration is1, the transmission direction configuration is one of theuplink-downlink configuration set {0, 1, 6}.

In addition, an uplink-downlink configuration of the downlink referenceconfiguration may be the same as an uplink-downlink configuration of theuplink reference configuration. However, in order for the mobile stationapparatus 1 which has not received the second information to set thesame uplink-downlink configuration as an uplink-downlink configurationof the uplink reference configuration as the downlink referenceconfiguration, an uplink-downlink configuration of the downlinkreference configuration indicated by the second information is notpreferably the same as an uplink-downlink configuration of the uplinkreference configuration indicated by the first information.

FIG. 17 is a diagram illustrating an example of communication betweenthe base station apparatus 3 and the mobile station apparatuses 1 (1Aand 1B) in the first embodiment of the present invention. In FIG. 17,the uplink reference configuration 0, the downlink referenceconfiguration 1, and the transmission direction configuration 6 are setin each of the mobile station apparatus 1A and the mobile stationapparatus 1B. In FIG. 17, the mobile station apparatus 1A succeeds indecoding an ACK, but the mobile station apparatus 1B detects the ACK asa NACK.

The Base station apparatus 3 transmits an uplink grant to each of themobile station apparatus 1A and the mobile station apparatus 1B via thePDCCH/EPDCCH in [SFN=m, subframe n=1].

Each of the mobile station apparatus 1A and the mobile station apparatus1B transmits data via a PUSCH corresponding to the uplink grant in[SFN=m, subframe n=8].

The base station apparatus 3 transmits a HARQ indicator indicating anACK to each of the mobile station apparatus 1A and the mobile stationapparatus 1B in [SFN=m+1, subframe n=5].

In addition, the base station apparatus 3 transmits a downlink grant toeach of the mobile station apparatus 1A and the mobile station apparatus1B via the PDCCH/EPDCCH and transmits data to each of the mobile stationapparatus 1A and the mobile station apparatus 1B via a PDSCHcorresponding to the PDCCH/EPDCCH, in [SFN=m+1, subframe n=9].

The mobile station apparatus 1A which has succeeded in decoding the ACKdoes not retransmit data via the PUSCH and monitors the PDCCH/EPDCCH in[SFN=m+1, subframe n=9].

The mobile station apparatus 1B which has succeeded in decoding the ACKdoes not retransmit data via the PUSCH and monitors the PDCCH/EPDCCH in[SFN=m+1, subframe n=9].

The mobile station apparatus 1B which has decoded the ACK as a NACKconsiders retransmission of data using the PUSCH to be scheduled in[SFN=m+1, subframe n=9], but does not retransmit the data via the PUSCHsince [SFN=m+1, subframe n=9] is indicated as a downlink subframe by thetransmission direction configuration. In addition, the mobile stationapparatus 1B monitors the PDCCH/EPDCCH in [SFN=m+1, subframe n=9].

In order to transmit a downlink signal in [SFN=m+1, subframe n=9], thebase station apparatus 3 may transmit a HARQ indicator indicating an ACKto each of the mobile station apparatus 1A and the mobile stationapparatus 1B in [SFN=m+1, subframe n=5] even if there is a failure indecoding the data received via the PUSCH in [SFN=m, subframe n=8].

The base station apparatus 3 of the first embodiment includes thesubframe setting portion 3013 that determines a downlink referenceconfiguration (second configuration) from a configuration set which isrestricted on the basis of an uplink reference configuration (firstconfiguration), and determines a transmission direction configuration(third configuration) from a configuration set which is restricted onthe basis of the uplink reference configuration (first configuration)and the downlink reference configuration (second configuration); and thetransmission unit 307 that transmits first information indicating theuplink reference configuration (first configuration), second informationindicating the downlink reference configuration (second configuration),and third information indicating the transmission directionconfiguration (third configuration).

The mobile station apparatus 1 of the first embodiment includes thereception unit 105 that receives first information indicating an uplinkreference configuration (first configuration), second informationindicating a downlink reference configuration (second configuration),and third information indicating a transmission direction configuration(third configuration); and the subframe setting portion 1013 that setsthe uplink reference configuration (first configuration), the downlinkreference configuration (second configuration), and the transmissiondirection configuration (third configuration).

As mentioned above, since the transmission direction configuration isused, the mobile station apparatus 1B can be prevented from making atransmission error of using a PUSCH in [SFN=m+1, subframe n=9], and thusit is possible to avoid the PUSCH from being transmitted by the mobilestation apparatus 1B and interfering with the mobile station apparatus1A, and thus the mobile station apparatus 1B can correctly monitor thePDCCH/EPDCCH.

In addition, since the transmission direction configuration is definedby an uplink-downlink configuration, it is possible to more efficientlyset a transmission direction than by using a method of giving aninstruction for a transmission direction for each subframe.

Hereinafter, a second embodiment of the present invention will bedescribed.

Hereinafter, unless otherwise stated, the content described in the firstembodiment can also be applied to the second embodiment. Hereinafter,unless otherwise stated, the mobile station apparatus 1 of the secondembodiment can perform the same process as that by the mobile stationapparatus 1 of the first embodiment, and the base station apparatus 3 ofthe second embodiment can perform the same process as that by the basestation apparatus 3 of the first embodiment.

In the second embodiment, as a configuration set which is restricted onthe basis of the uplink reference configuration (first configuration)and the downlink reference configuration (second configuration), aconfiguration set (configurations of the set) is used which isconstituted by uplink-downlink configurations of the uplink referenceconfiguration (first configuration) and uplink-downlink configurationsof the downlink reference configuration (second configuration).

FIG. 18 is a diagram illustrating an uplink reference configuration, adownlink reference configuration, and a transmission directionconfiguration, in the second embodiment of the present invention.

For example, in FIG. 18, in a case where an uplink-downlinkconfiguration of the uplink reference configuration is 0 and anuplink-downlink configuration of the downlink reference configuration is1, the transmission direction configuration is one of theuplink-downlink configuration set {0, 1}.

The subframe setting portion 3013 of the base station apparatus 3 of thesecond embodiment determines the transmission direction configuration(third configuration) from a configuration set (configurations of theset) constituted by uplink-downlink configurations of the uplinkreference configuration (first configuration) and uplink-downlinkconfigurations of the downlink reference configuration (secondconfiguration). The subframe setting portion 3013 of the base stationapparatus 3 of the second embodiment determines where a transmissiondirection is based on the uplink reference configuration or the downlinkreference configuration. The transmission unit 307 of the base stationapparatus 3 of the second embodiment transmits fourth informationindicating whether a transmission direction is based the uplinkreference configuration or the downlink reference configuration, insteadof the third information.

The reception unit 105 of the mobile station apparatus 1 of the secondembodiment receives the fourth information instead of the thirdinformation. The subframe setting portion 1013 of the mobile stationapparatus 1 of the second embodiment sets whether a transmissiondirection is based on the uplink reference configuration or the downlinkreference configuration, on the basis of the fourth information. Thesubframe setting portion 1013 of the mobile station apparatus 1 of thesecond embodiment sets the third configuration on the basis of thereceived fourth information.

The fourth information may be information indicating a transmissiondirection configuration (third configuration) selected from aconfiguration set (configurations of the set) constituted byuplink-downlink configurations of the uplink reference configuration anduplink-downlink configurations of the downlink reference configuration.The fourth information preferably has 1 bit.

The fourth information indicates that a subframe in which an uplinksignal (for example, a PUSCH and/or an SRS) can be transmitted is to bespecified on the basis of one of the uplink reference configuration andthe downlink reference configuration. The subframe setting portion 1013of the mobile station apparatus 1 specifies a subframe in which uplinktransmission can be performed, on the basis of an uplink referenceconfiguration or a downlink reference configuration indicated by thefourth information.

The fourth information indicates that a subframe for monitoring adownlink signal is to be specified on the basis of one of the uplinkreference configuration and the downlink reference configuration. Thesubframe setting portion 1013 of the mobile station apparatus 1specifies a subframe for monitoring a downlink signal, on the basis ofan uplink reference configuration or a downlink reference configurationindicated by the fourth information.

In a case where uplink transmission is scheduled/set in a subframe whichis regarded as uplink transmission not being possible on the basis of anuplink reference configuration or a downlink reference configurationindicated by the fourth information, the mobile station apparatus 1 doesnot perform the uplink transmission process in the subframe.

In a case where a PUSCH is scheduled to be transmitted in a subframewhich is regarded as PUSCH transmission not being possible on the basisof an uplink reference configuration or a downlink referenceconfiguration indicated by the fourth information, the mobile stationapparatus 1 does not transmit the PUSCH in the subframe.

In a case where an SRS is scheduled to be transmitted in a subframewhich is regarded as SRS transmission not being possible on the basis ofan uplink reference configuration or a downlink reference configurationindicated by the fourth information, the mobile station apparatus 1 doesnot transmit the SRS in the subframe.

As mentioned above, the transmission direction configuration isdetermined from a configuration set (configurations of the set)constituted by uplink-downlink configurations of the uplink referenceconfiguration and uplink-downlink configurations of the downlinkreference configuration, and thus it is possible to further reduce thenumber of bits of the fourth information than in the third informationof the first embodiment.

Hereinafter, a third embodiment of the present invention will bedescribed.

Hereinafter, unless otherwise stated, the content described in the firstor second embodiment can also be applied to the third embodiment.Hereinafter, unless otherwise stated, the mobile station apparatus 1 ofthe third embodiment can perform the same process as that by the mobilestation apparatus 1 of the first or second embodiment, and the basestation apparatus 3 of the third embodiment can perform the same processas that by the base station apparatus 3 of the first or secondembodiment.

In the same manner as in the mobile station apparatus 1 of the first orsecond embodiment, the mobile station apparatus 1 of the thirdembodiment specifies (selects, determines) a transmission direction(up/down) on the basis of a transmission direction configuration. In thethird embodiment, the mobile station apparatus 1 further specifies(selects, determines) a transmission direction (up/down) of a period inwhich a transmission direction configuration is not set.

In a case where an uplink reference configuration, a downlink referenceconfiguration, and a transmission direction configuration, the mobilestation apparatus 1 specifies (selects, determines) a transmissiondirection (up/down) on the basis of the transmission directionconfiguration.

In a case where an uplink reference configuration is set, and a downlinkreference configuration and a transmission direction configuration arenot set, the mobile station apparatus 1 specifies (selects, determines)a transmission direction (up/down) on the basis of the uplink referenceconfiguration.

In a case where an uplink reference configuration and a downlinkreference configuration are set, and a transmission directionconfiguration is not set, the mobile station apparatus 1 specifies(selects, determines) a transmission direction (up/down) on the basis ofthe downlink reference configuration. In other words, the uplinkreference configuration and the downlink reference configuration areset, and an instruction for the transmission direction configuration isnot given, the mobile station apparatus 1 sets an uplink-downlinkconfiguration of the downlink reference configuration to thetransmission direction configuration as a default.

The mobile station apparatus 1 in which the uplink referenceconfiguration, the downlink reference configuration, and thetransmission direction configuration have been set may clear/discard thetransmission direction configuration in a case where the downlinkreference configuration is reset. In addition, the mobile stationapparatus 1 in which the uplink reference configuration, the downlinkreference configuration, and the transmission direction configurationhave been set may not clear/discard the transmission directionconfiguration in a case where the reset downlink reference configurationis the same as the previous downlink reference configuration. In otherwords, the mobile station apparatus 1 in which the uplink referenceconfiguration, the downlink reference configuration, and thetransmission direction configuration have been set may clear/discard thetransmission direction configuration in a case where the downlinkreference configuration is changed.

In a period/case in which the transmission direction configuration isnot set, the subframe setting portion 1013 of the mobile stationapparatus 1 of the third embodiment specifies (selects, determines) atransmission direction (up/down) on the basis of the downlink referenceconfiguration. In addition, in a case where the downlink referenceconfiguration is reset/changed, the subframe setting portion 1013 of themobile station apparatus 1 of the third embodiment may clear/discard thetransmission direction configuration.

In a case where the mobile station apparatus 1 is instructed toreset/change the downlink reference configuration, the subframe settingportion 3013 of the mobile station apparatus 3 of the third embodimentmay regard the transmission direction configuration of the mobilestation apparatus 1 as being cleared/discarded.

FIG. 19 is a sequence diagram illustrating an example of the thirdembodiment of the present invention.

In T1900, the base station apparatus 3 transmits the first information.In T1902, the mobile station apparatus 1 sets an uplink referenceconfiguration on the basis of the first information. In T1904, the basestation apparatus 3 transmits the second information. In T1906, themobile station apparatus 1 sets a downlink reference configuration onthe basis of the second information. In T1908, the base stationapparatus 3 transmits the third information or the fourth information.In T1910, the mobile station apparatus 1 sets a transmission directionconfiguration on the basis of the third information or the fourthinformation.

In T1912, the base station apparatus 3 transmits the second information.In T1914, the mobile station apparatus 1 resets a downlink referenceconfiguration on the basis of the second information, andclears/discards the transmission direction configuration set in T1910.In T1916, the base station apparatus 3 transmits the third informationor the fourth information. In T1918, the mobile station apparatus 1resets a transmission direction configuration on the basis of the thirdinformation or the fourth information.

In a period P1940 until the downlink reference configuration isinitially set, the mobile station apparatus 1 specifies (selects,determines) a transmission direction (up/down) on the basis of theuplink reference configuration.

In a period P1942 after the downlink reference configuration is setuntil the transmission direction configuration is initially set, themobile station apparatus 1 specifies (selects, determines) atransmission direction (up/down) on the basis of the downlink referenceconfiguration.

In a period P1944 after the transmission direction configuration is setuntil the transmission direction configuration is cleared, the mobilestation apparatus 1 specifies (selects, determines) a transmissiondirection (up/down) on the basis of the transmission directionconfiguration.

In a period P1946 after the transmission direction configuration iscleared (the downlink reference configuration is reset/changed) untilthe next transmission direction configuration is set, the mobile stationapparatus 1 specifies (selects, determines) a transmission direction(up/down) on the basis of the downlink reference configuration.

In a period P1948 after the downlink reference configuration is set, themobile station apparatus 1 specifies (selects, determines) atransmission direction (up/down) on the basis of the transmissiondirection configuration.

In addition, in T1902, the mobile station apparatus 1 may set an uplinkreference configuration and a downlink reference configuration on thebasis of the first information, and, in T1906, the mobile stationapparatus 1 may reset a downlink reference configuration on the basis ofthe second information. In this case, in the period P1940, the mobilestation apparatus 1 specifies (selects, determines) a transmissiondirection (up/down) on the basis of the downlink referenceconfiguration.

The mobile station apparatus 1 receives the second information,determines a subframe in which an uplink signal can be transmitted onthe basis of the second information, and then monitors whether or notthe third information or the fourth information is received. If thethird information or fourth is received, a subframe is determined inwhich an uplink signal can be transmitted on the basis of the thirdinformation or the fourth information.

For example, the base station apparatus 3 transmits the thirdinformation or the fourth information to the mobile station apparatus 1by using the PDCCH/EPDCCH. The third information or the fourthinformation is used to control a dynamic TDD operation in coverage ofthe base station apparatus 3 (cell). The third information or the fourthinformation is transmitted in common to a plurality of mobile stationapparatuses 1. The third information or the fourth information istransmitted and received in a common search space (CSS) or a UE-specificsearch space (USS).

The CSS is a common space in which the plurality of mobile stationapparatuses 1 monitor the PDCCH/EPDCCH. The USS is a space which isdefined on the basis of at least a C-RNTI. The C-RNTI is an identifierwhich is uniquely assigned to the mobile station apparatus 1.

Not the C-RNTI but a common identifier is preferably used for thePDCCH/EPDCCH which is used to transmit and receive the third informationor the fourth information. In addition, a subframe may be restrictedwhich is used for the mobile station apparatus 1 to monitor thePDCCH/EPDCCH including the third information or the fourth information.The base station apparatus 3 may control a subframe which is used forthe mobile station apparatus 1 to monitor the PDCCH/EPDCCH including thethird information or the fourth information.

For example, the PDCCH/EPDCCH including the third information or thefourth information may be allocated at intervals of ten subframes. Forexample, the mobile station apparatus 1 monitors the third informationat intervals of ten subframes. A subframe in which the PDCCH/EPDCCHincluding the third information may be determined in advance. Forexample, the third information may be allocated only in the subframe 0of the radio frame.

The base station apparatus 3 transmits the third information or thefourth information only in a case where it is determined that the thirdinformation is necessary. For example, in a case where it is determinedthat the transmission direction configuration is changed, the basestation apparatus 3 transmits the third information or the fourthinformation. For example, in a case where it is determined that themobile station apparatus 1 which starts a dynamic TDD operation isrequired to be notified of the third information, the base stationapparatus 3 transmits the third information or the fourth informationthereto.

The mobile station apparatus 1 which starts the dynamic TDD operationmonitors downlink control information including the third information orthe fourth information in a subframe in which the PDCCH/EPDCCH includingthe third information or the fourth information is allocated.

The mobile station apparatus 1 tries to decode a received signal anddetermines whether or not the PDCCH/EPDCCH including the thirdinformation or the fourth information is detected. In a case where thePDCCH/EPDCCH including the third information or the fourth informationis detected, the mobile station apparatus 1 determines a subframe inwhich an uplink signal can be transmitted on the basis of the detectedthird information or the fourth information. In a case where thePDCCH/EPDCCH including the third information or the fourth informationis not detected, the mobile station apparatus 1 may maintain adetermination hitherto regarding a subframe in which an uplink signalcan be transmitted.

As mentioned above, in a period/case in which a transmission directionconfiguration is not set, a transmission direction (up/down) isspecified (selected, determined) on the basis of not an uplink referenceconfiguration but a downlink reference configuration, and thus it ispossible to further reduce a probability that the mobile stationapparatus 1 may erroneously perform uplink transmission.

For example, even if the third information indicates, as a downlinksubframe, a subframe which is indicated as an uplink subframe by anuplink reference configuration but is indicated as a downlink subframeby a downlink reference configuration, and the mobile station apparatus1 fails to decode the third information, it is possible to prevent themobile station apparatus 1 from performing uplink transmission in thesubframe.

In addition, in a case where an uplink reference configuration is reset,the mobile station apparatus 1 in which the uplink referenceconfiguration, a downlink reference configuration, and a transmissiondirection configuration have been set may clear/discard the downlinkreference configuration and the transmission direction configuration.

Hereinafter, a fourth embodiment of the present invention will bedescribed.

Hereinafter, unless otherwise stated, the content described in the firstto third embodiments can also be applied to the fourth embodiment.Hereinafter, unless otherwise stated, the mobile station apparatus 1 ofthe fourth embodiment can perform the same process as that by the mobilestation apparatus 1 of the first to third embodiments, and the basestation apparatus 3 of the fourth embodiment can perform the sameprocess as that by the base station apparatus 3 of the first to thirdembodiments.

The subframe setting portion 1013 of the mobile station apparatus 1 ofthe fourth embodiment manages a timer. The subframe setting portion 1013makes a transmission direction configuration valid only in a period inwhich the timer is running. If the timer starts once, the timer isrunning until the timer stops or the timer expires. Otherwise, the timeris not running.

The subframe setting portion 1013 starts the timer when a transmissiondirection configuration is set. The subframe setting portion 1013 maystart the timer in a case where the third information or the fourthinformation indicating a transmission direction configuration isreceived.

If the timer has already run when a transmission direction configurationi set, the subframe setting portion 1013 restarts the timer. If thetimer has already run when the third information or the fourthinformation indicating a transmission direction configuration isreceived, the subframe setting portion 1013 may restart the timer.

When an uplink reference configuration or a downlink referenceconfiguration is reset/changed, the subframe setting portion 1013 clearsthe transmission direction configuration and stops the timer. When thetimer expires, the subframe setting portion 1013 clears the transmissiondirection configuration.

The subframe setting portion 3013 of the base station apparatus 3 of thefourth embodiment determines a configuration (for example, duration of atimer) regarding the timer, generates fifth information indicating theconfiguration regarding the timer, and transmits the fifth informationto the mobile station apparatus 1 via the transmission unit 307. Thesubframe setting portion 1013 of the mobile station apparatus 1 sets theconfiguration regarding the timer on the basis of the fifth information.

In addition, the duration of the timer may be infinite. Further, thefifth information may be transmitted along with the second information.Still further, the fifth information may be transmitted along with thethird information or the fourth information.

FIG. 20 is a sequence diagram illustrating an example of the fourthembodiment of the present invention. In FIG. 20, in a period P2040 and aperiod P2042, the timer is running.

In T2000, the base station apparatus 3 transmits the first information.In T2002, the mobile station apparatus 1 sets an uplink referenceconfiguration on the basis of the first information. In T2004, the basestation apparatus 3 transmits the second information and the fifthinformation. In T2006, the mobile station apparatus 1 sets a downlinkreference configuration on the basis of the second information, and setsa configuration regarding the timer on the basis of the fifthinformation. In T2008, the base station apparatus 3 transmits the thirdinformation or the fourth information.

In T2010, the mobile station apparatus 1 sets a transmission directionconfiguration on the basis of the third information or the fourthinformation, and starts the timer. In T2012, the timer expires, and themobile station apparatus 1 clears the transmission directionconfiguration. In T2014, the base station apparatus 3 transmits thethird information or the fourth information. In T2016, the mobilestation apparatus 1 sets a transmission direction configuration again onthe basis of the third information or the fourth information, and startsthe timer. In T2018, the base station apparatus 3 transmits the thirdinformation or the fourth information.

In T2020, the mobile station apparatus 1 sets/resets/changes atransmission direction configuration on the basis of the thirdinformation or the fourth information, and restarts the timer. In T2022,the base station apparatus 3 transmits the second information. In T2024,the mobile station apparatus 1 sets/resets/changes a transmissiondirection configuration on the basis of the second information, stopsthe timer, and clears the transmission direction configuration.

As mentioned above, since the timer is used, it is possible to furtherreduce a probability that the mobile station apparatus 1 may erroneouslyperform uplink transmission.

For example, even if the mobile station apparatus 1 fails to decode thethird information for resetting a transmission direction configuration,the mobile station apparatus 1 clears the transmission directionconfiguration on the basis of expiration of the timer, and does not anuplink transmission process in a subframe which is indicated as anuplink subframe by an uplink reference configuration but is indicated asa downlink reference configuration by a downlink referenceconfiguration. Thus, it is possible to prevent the mobile stationapparatus 1 from performing uplink transmission in the subframe.

Hereinafter, a fifth embodiment of the present invention will bedescribed.

Hereinafter, unless otherwise stated, the content described in the firstto third embodiments can also be applied to the fifth embodiment.Hereinafter, unless otherwise stated, the mobile station apparatus 1 ofthe fifth embodiment can perform the same process as that by the mobilestation apparatus 1 of the first to third embodiments, and the basestation apparatus 3 of the fifth embodiment can perform the same processas that by the base station apparatus 3 of the first to thirdembodiments.

The base station apparatus 3 of the fifth embodiment transmits an MIBincluding the third information or the fourth information to the mobilestation apparatus 1.

The mobile station apparatus 1 of the fifth embodiment specifies aperiod in which a transmission direction configuration is valid on thebasis of a transmission periodicity of the MIB. The mobile stationapparatus 1 may regard that a transmission direction configuration in acertain MIB transmission periodicity is valid until a subframe in whichthe transmission direction configuration can be reset by an MIB which isinitially transmitted in the next MIB transmission periodicity.

FIG. 21 is a diagram illustrating an example of the fifth embodiment ofthe present invention. Initial transmission of the MIB is performed in asubframe 0 of a radio frame satisfying SFN mod 4=0, and retransmission(repetition) of the MIB is performed in subframes 0 of all other radioframes. In FIG. 21, the MIB transmitted in T2100 is repeatedlytransmitted in T2102, T2104, and T2106.

In T2100 of FIG. 21, the mobile station apparatus 1 fails to decode theMIB which is transmitted via a PBCH. In T2102 of FIG. 21, the mobilestation apparatus 1 succeeds in decoding the MIB which is retransmittedvia the PBCH. In T2104 and T2106 of FIG. 21, the mobile stationapparatus 1 may not try to decode the MIB. In T2108 of FIG. 21, themobile station apparatus 1 tries to decode the MIB which is initiallytransmitted in the next MIB transmission periodicity.

In FIG. 21, in a case where the MIB including the third information orthe fourth information is received via the PBCH in a subframe n−k(T2102), the mobile station apparatus 1 sets (makes valid) atransmission direction configuration in a subframe n (T2110). Forexample, k is 4. For example, k is determined on the basis of the tableof FIG. 13 and a downlink reference configuration.

The mobile station apparatus 1 makes the transmission directionconfiguration valid in a period P2140. The mobile station apparatus 1may clear the transmission direction configuration in a subframe (T2112)which is k or k−1 later than a subframe (T2108) in which the MIB isinitially transmitted in the next MIB transmission periodicity.

In addition, in a period in which a transmission direction configurationis not set, the mobile station apparatus 1 preferably specifies(selects, determines) a transmission direction on the basis of adownlink reference configuration.

As mentioned above, the mobile station apparatus 1 specifies a period inwhich a transmission direction configuration is valid on the basis of anMIB transmission periodicity, and thus it is possible to reduce aprobability that the mobile station apparatus 1 may erroneously performuplink transmission.

A program which runs in the base station apparatus 3 and the mobilestation apparatus 1 according to the present invention is a program(which causes a computer to function) which controls a centralprocessing unit (CPU) and the like to realize the functions of theembodiments according to the present invention. In addition, theinformation treated in these devices is temporarily accumulated in arandom access memory (RAM) during processing thereof, is then stored invarious ROMs such as a flash read only memory (ROM) or hard disk drives(HDDs), and is read by the CPU as necessary so as to be corrected and bewritten.

In addition, part of the mobile station apparatus 1 and the base stationapparatus 3 in the above-described embodiments may be realized by acomputer. In this case, a program for realizing the control function isrecorded on a computer readable recording medium, and the controlfunction may be realized by a computer system reading and executing theprogram recorded on the recording medium.

In addition, the “computer system” mentioned here is a computer systemwhich is built into the mobile station apparatus 1 or the base stationapparatus 3, and includes hardware such as an OS or peripheral devices.Further, the “computer readable recording medium” refers to a portablemedium such as a flexible disk, a magneto-optical disc, a ROM, or aCD-ROM, and a storage device such as a hard disk built into the computersystem.

Furthermore, the “computer readable recording medium” may also includeone which dynamically holds a program for a short period of time, suchas a communication line in a case where the program is transmitted via anetwork such as the Internet or a communication line such as a telephoneline, and one which holds the program for a specific time, such as anonvolatile memory of the computer system which becomes a server or aclient in this case. Moreover, the program may be one which realizessome of the above-described functions, and may be one which realizes theabove-described functions in combination with a program which hasalready been recorded in the computer system.

In addition, the base station apparatus 3 of the above-describedembodiments may be realized as an aggregate (device groups) constitutedby a plurality of devices. Each of the devices constituting the devicegroup may include each function, or some or all of the functional blocksof the base station apparatus 3 according to the embodiments. The devicegroup may have each general function or each general functional block ofthe base station apparatus 3. Further, the mobile station apparatus 1according to the above-described embodiments may communicate with thebase station apparatus as an aggregate.

In addition, the base station apparatus 3 in the above-describedembodiments may be an evolved universal terrestrial radio access network(EUTRAN). Further, the base station apparatus 3 in the above-describedembodiments may have some or all of the functions of the higher node ofeNodeB.

Further, part or the whole of the mobile station apparatus 1 and thebase station apparatus 3 in the above-described embodiments may betypically implemented by an LSI which is an integrated circuit, and maybe realized by a chip set. The respective functional blocks of themobile station apparatus 1 and the base station apparatus 3 may beseparately formed of a chip, and some or all of the blocks may beintegrally formed as a chip. Further, a technique for an integratedcircuit is not limited to an LSI, and may be realized by a dedicatedcircuit or a general purpose processor. Furthermore, in a case where atechnique for an integrated circuit which replaces the LSI appears withthe advance of semiconductor techniques, an integrated circuit based onsuch a technique may be used.

In addition, in the above-described embodiments, a mobile stationapparatus has been described as an example of a terminal apparatus or acommunication apparatus, but the present invention is not limitedthereto, and is applicable to terminal apparatuses or communicationapparatuses, such as non-movable or stationary electronic apparatusesinstalled indoors or outdoors, for example, AV apparatuses, kitchenapparatuses, cleaning and washing apparatuses, air-conditioningapparatuses, vending machines, and other pieces of household equipment.

As mentioned above, although the embodiments of the present inventionhave been described in detail with reference to the drawings, a specificconfiguration is not limited to the embodiments, and designmodifications and the like may occur within the scope without departingfrom the spirit of the invention. In addition, various alterations mayoccur in the claims of the present invention, and embodiments obtainedby appropriately combining technical means which are respectivelydisclosed in different embodiments are also included in the technicalscope of the present invention. Further, configurations in which theelements which are disclosed in the above-described respectiveembodiments and achieve the same effect are replaced with each other arealso included in the technical scope of the present invention.

DESCRIPTION OF REFERENCE NUMERALS

-   -   1 (1A, 1B, 1C): MOBILE STATION APPARATUS    -   3: BASE STATION APPARATUS    -   101: HIGHER LAYER PROCESSING UNIT    -   103: CONTROL UNIT    -   105: RECEPTION UNIT    -   107: TRANSMISSION UNIT    -   301: HIGHER LAYER PROCESSING UNIT    -   303 CONTROL UNIT    -   305: RECEPTION UNIT    -   307: TRANSMISSION UNIT    -   1011: RADIO RESOURCE CONTROL PORTION    -   1013: SUBFRAME SETTING PORTION    -   1015: SCHEDULING INFORMATION ANALYSIS PORTION    -   3011: RADIO RESOURCE CONTROL PORTION    -   3013: SUBFRAME SETTING PORTION    -   3015: SCHEDULING PORTION

The invention claimed is:
 1. A base station apparatus configured tocommunicate with a terminal apparatus configured with a serving cell,the base station apparatus comprising: a transmission circuit configuredto, programmed to, or configured and programmed to transmit to theterminal apparatus, first information indicating an uplink-referenceconfiguration, second information indicating a downlink-referenceconfiguration, and third information indicating a transmission directionconfiguration, each of the uplink-reference configuration, thedownlink-reference configuration, and the transmission directionconfiguration is defined by an uplink-downlink configuration; and areception circuit configured to, programmed to, or configured andprogrammed to receive from the terminal apparatus, a physical uplinkshared channel corresponding to a physical downlink control channelbased on at least the uplink-reference configuration, and receive fromthe terminal apparatus, an HARQ-ACK (Hybrid Automatic Repeat reQuestACKnowledgement) corresponding to a physical downlink shared channelbased on at least the downlink-reference configuration, wherein thetransmission direction configuration is used by the terminal apparatusto monitor a plurality of physical downlink control channels, a subframewhich is indicated as a downlink subframe or a special subframe by theuplink-reference configuration is not indicated as an uplink subframe bythe downlink-reference configuration, a subframe indicated as an uplinksubframe or a special subframe by the downlink-reference configurationis not indicated as a downlink subframe by the transmission directionconfiguration, and a subframe indicated as a downlink subframe or aspecial subframe by the uplink-reference configuration is not indicatedas an uplink subframe by the transmission direction configuration.
 2. Aterminal apparatus configured with a serving cell and configured tocommunicate with a base station apparatus, the terminal apparatuscomprising: a reception circuit configured to, programmed to, orconfigured and programmed to receive from the base station apparatus,first information indicating an uplink-reference configuration, secondinformation indicating a downlink-reference configuration, and thirdinformation indicating a transmission direction configuration, each ofthe uplink-reference configuration, the downlink-referenceconfiguration, and the transmission direction configuration is definedby an uplink-downlink configuration; and a transmission circuitconfigured to, programmed to, or configured and programmed to transmitto the base station apparatus, a physical uplink shared channelcorresponding to a physical downlink control channel based on at leastthe uplink-reference configuration, and transmit to the base stationapparatus, an HARQ-ACK (Hybrid Automatic Repeat reQuest ACKnowledgement)corresponding to a physical downlink shared channel based on at leastthe downlink-reference configuration, wherein the transmission directionconfiguration is used by the terminal apparatus to monitor a pluralityof physical downlink control channels, a subframe which is indicated asa downlink subframe or a special subframe by the uplink-referenceconfiguration is not indicated as an uplink subframe by thedownlink-reference configuration, a subframe indicated as an uplinksubframe or a special subframe by the downlink-reference configurationis not indicated as a downlink subframe by the transmission directionconfiguration, and a subframe indicated as a downlink subframe or aspecial subframe by the uplink-reference configuration is not indicatedas an uplink subframe by the transmission direction configuration.
 3. Awireless communication method for a base station apparatus configured tocommunicate with a terminal apparatus configured with a serving cell,the wireless communication method comprising: transmitting to theterminal apparatus, first information indicating an uplink-referenceconfiguration, second information indicating a downlink-referenceconfiguration, and third information indicating a transmission directionconfiguration, each of the uplink-reference configuration, thedownlink-reference configuration, and the transmission directionconfiguration is defined by an uplink-downlink configuration; receivingfrom the terminal apparatus, a physical uplink shared channelcorresponding to a physical downlink control channel based on at leastthe uplink-reference configuration; and receiving from the terminalapparatus, an HARQ-ACK (Hybrid Automatic Repeat reQuest ACKnowledgement)corresponding to a physical downlink shared channel based on at leastthe downlink-reference configuration, wherein the transmission directionconfiguration is used by the terminal apparatus to monitor a pluralityof physical downlink control channels, a subframe which is indicated asa downlink subframe or a special subframe by the uplink-referenceconfiguration is not indicated as an uplink subframe by thedownlink-reference configuration, a subframe indicated as an uplinksubframe or a special subframe by the downlink-reference configurationis not indicated as a downlink subframe by the transmission directionconfiguration, and a subframe indicated as a downlink subframe or aspecial subframe by the uplink-reference configuration is not indicatedas an uplink subframe by the transmission direction configuration.
 4. Awireless communication method for a terminal apparatus configured with aserving cell and configured to communicate with a base stationapparatus, the wireless communication method comprising: receiving fromthe base station apparatus, first information indicating anuplink-reference configuration, second information indicating adownlink-reference configuration, and third information indicating atransmission direction configuration, each of the uplink-referenceconfiguration, the downlink-reference configuration, and thetransmission direction configuration is defined by an uplink-downlinkconfiguration; transmitting to the base station apparatus, a physicaluplink shared channel corresponding to a physical downlink controlchannel based on at least the uplink-reference configuration; andtransmitting to the base station apparatus, an HARQ-ACK (HybridAutomatic Repeat reQuest ACKnowledgement) corresponding to a physicaldownlink shared channel based on at least the downlink-referenceconfiguration, wherein the transmission direction configuration is usedby the terminal apparatus to monitor a plurality of physical downlinkcontrol channels, a subframe which is indicated as a downlink subframeor a special subframe by the uplink-reference configuration is notindicated as an uplink subframe by the downlink reference configuration,a subframe indicated as an uplink subframe or a special subframe by thedownlink-reference configuration is not indicated as a downlink subframeby the transmission direction configuration, and a subframe indicated asa downlink subframe or a special subframe by the uplink-referenceconfiguration is not indicated as an uplink subframe by the transmissiondirection configuration.